@ohos.fileio (File Management)

The fileio module provides APIs for file storage and management, including basic file management, directory management, file information statistics, and stream read and write.

NOTE

• The initial APIs of this module are supported since API version 6. Newly added APIs will be marked with a superscript to indicate their earliest API version.
• The APIs provided by this module are deprecated since API version 9. You are advised to use @ohos.file.fs.

Modules to Import

import fileio from '@ohos.fileio';

Guidelines

Before using the APIs provided by this module to perform operations on a file or directory, obtain the application sandbox path of the file or directory as follows:

Stage Model

 import UIAbility from '@ohos.app.ability.UIAbility';
 import window from '@ohos.window';

 export default class EntryAbility extends UIAbility {
   onWindowStageCreate(windowStage: window.WindowStage) {
     let context = this.context;
     let pathDir = context.filesDir;
   }
 }

For details about how to obtain the stage model context, see UIAbilityContext.

FA Model

import featureAbility from '@ohos.ability.featureAbility';

let context = featureAbility.getContext();
context.getFilesDir().then((data) => {
  let pathDir = data;
})

For details about how to obtain the FA model context, see Context.

fileio.stat

stat(path: string): Promise<Stat>

Obtains file information. This API uses a promise to return the result.

NOTE

This API is deprecated since API version 9. Use fs.stat instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the file.

Return value

Type	Description
Promise<Stat>	Promise used to return the file information obtained.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "test.txt";
fileio.stat(filePath).then((stat: fileio.Stat) => {
  console.info("getFileInfo succeed, the size of file is " + stat.size);
}).catch((err: BusinessError) => {
  console.info("getFileInfo failed with error:" + err);
});

fileio.stat

stat(path: string, callback: AsyncCallback<Stat>): void

Obtains file information. This API uses an asynchronous callback to return the result.

NOTE

This API is deprecated since API version 9. Use fs.stat instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the file.
callback	AsyncCallback<Stat>	Yes	Callback invoked to return the file information obtained.

Example

import { BusinessError } from '@ohos.base';
fileio.stat(pathDir, (err: BusinessError, stat: fileio.Stat) => {
  // Example code in Stat
});

fileio.statSync

statSync(path: string): Stat

Obtains file information. This API returns the result synchronously.

NOTE

This API is deprecated since API version 9. Use fs.statSync instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the file.

Return value

Type	Description
Stat	File information obtained.

Example

let stat = fileio.statSync(pathDir);
// Example code in Stat

fileio.opendir

opendir(path: string): Promise<Dir>

Opens a directory. This API uses a promise to return the result.

NOTE

This API is deprecated since API version 9. Use fs.listFile instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the directory to open.

Return value

Type	Description
Promise<Dir>	Promise used to return the Dir object opened.

Example

import { BusinessError } from '@ohos.base';
let dirPath = pathDir + "/testDir";
fileio.opendir(dirPath).then((dir: fileio.Dir) => {
  console.info("opendir succeed");
}).catch((err: BusinessError) => {
  console.info("opendir failed with error:" + err);
});

fileio.opendir

opendir(path: string, callback: AsyncCallback<Dir>): void

Opens a file directory. This API uses an asynchronous callback to return the result.

NOTE

This API is deprecated since API version 9. Use fs.listFile instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the directory to open.
callback	AsyncCallback<Dir>	Yes	Callback invoked when the directory is open asynchronously.

Example

import { BusinessError } from '@ohos.base';
fileio.opendir(pathDir, (err: BusinessError, dir: fileio.Dir) => {
  // Example code in Dir struct
  // Use read/readSync/close.
});

fileio.opendirSync

opendirSync(path: string): Dir

Opens a directory. This API returns the result synchronously.

NOTE

This API is deprecated since API version 9. Use fs.listFileSync instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the directory to open.

Return value

Type	Description
Dir	A Dir instance corresponding to the directory.

Example

let dir = fileio.opendirSync(pathDir);
// Example code in Dir struct
// Use read/readSync/close.

fileio.access

access(path: string, mode?: number): Promise<void>

Checks whether the current process can access a file. This API uses a promise to return the result.

NOTE

This API is deprecated since API version 9. Use fs.access instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the file.
mode	number	No	Options for accessing the file. You can specify multiple options, separated with a bitwise OR operator (|). The default value is 0. The options are as follows: - 0: Check whether the file exists. - 1: Check whether the process has the execute permission on the file. - 2: Check whether the process has the write permission on the file. - 4: Check whether the process has the read permission on the file.

Return value

Type	Description
Promise<void>	Promise that returns no value.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
fileio.access(filePath).then(() => {
  console.info("Access successful");
}).catch((err: BusinessError) => {
  console.info("access failed with error:" + err);
});

fileio.access

access(path: string, mode?: number, callback: AsyncCallback<void>): void

Checks whether the current process can access a file. This API uses an asynchronous callback to return the result.

NOTE

This API is deprecated since API version 9. Use fs.access instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the file.
mode	number	No	Options for accessing the file. You can specify multiple options, separated with a bitwise OR operator (|). The default value is 0. The options are as follows: - 0: Check whether the file exists. - 1: Check whether the process has the execute permission on the file. - 2: Check whether the process has the write permission on the file. - 4: Check whether the process has the read permission on the file.
callback	AsyncCallback<void>	Yes	Callback invoked when the file is asynchronously checked.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
fileio.access(filePath, (err: BusinessError) => {
  // Do something.
});

fileio.accessSync

accessSync(path: string, mode?: number): void

Checks whether the current process can access the specified file. This API returns the result synchronously.

NOTE

This API is deprecated since API version 9. Use fs.accessSync instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the file.
mode	number	No	Options for accessing the file. You can specify multiple options, separated with a bitwise OR operator (|). The default value is 0. The options are as follows: - 0: Check whether the file exists. - 1: Check whether the process has the execute permission on the file. - 2: Check whether the process has the write permission on the file. - 4: Check whether the process has the read permission on the file.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
try {
  fileio.accessSync(filePath);
} catch(err: BusinessError) {
  console.info("accessSync failed with error:" + err);
}

fileio.close⁷⁺

close(fd: number): Promise<void>

Closes a file. This API uses a promise to return the result.

NOTE

This API is deprecated since API version 9. Use fs.close instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
fd	number	Yes	File descriptor of the file to close.

Return value

Type	Description
Promise<void>	Promise that returns no value.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
let fd = fileio.openSync(filePath);
fileio.close(fd).then(() => {
  console.info("File closed");
}).catch((err: BusinessError) => {
  console.info("close file failed with error:" + err);
});

fileio.close⁷⁺

close(fd: number, callback: AsyncCallback<void>): void

Closes a file. This API uses an asynchronous callback to return the result.

NOTE

This API is deprecated since API version 9. Use fs.close instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
fd	number	Yes	File descriptor of the file to close.
callback	AsyncCallback<void>	Yes	Callback invoked immediately after the file is closed.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
let fd = fileio.openSync(filePath);
fileio.close(fd, (err: BusinessError) => {
  // Do something.
});

fileio.closeSync

closeSync(fd: number): void

Closes a file. This API returns the result synchronously.

NOTE

This API is deprecated since API version 9. Use fs.closeSync instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
fd	number	Yes	File descriptor of the file to close.

Example

let filePath = pathDir + "/test.txt";
let fd = fileio.openSync(filePath);
fileio.closeSync(fd);

fileio.copyFile

copyFile(src: string|number, dest: string|number, mode?: number): Promise<void>

Copies a file. This API uses a promise to return the result.

NOTE

This API is deprecated since API version 9. Use fs.copyFile instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
src	string|number	Yes	Path or file descriptor of the file to copy.
dest	string|number	Yes	Path or file descriptor of the new file.
mode	number	No	Whether to overwrite the file with the same name in the destination directory. The default value is 0, which is the only value supported. 0: overwrite the file with the same name and truncate the part that is not overwritten.

Return value

Type	Description
Promise<void>	Promise that returns no value.

Example

import { BusinessError } from '@ohos.base';
let srcPath = pathDir + "srcDir/test.txt";
let dstPath = pathDir + "dstDir/test.txt";
fileio.copyFile(srcPath, dstPath).then(() => {
  console.info("File copied");
}).catch((err: BusinessError) => {
  console.info("copyFile failed with error:" + err);
});

fileio.copyFile

copyFile(src: string|number, dest: string|number, mode: number, callback: AsyncCallback<void>): void

Copies a file. This API uses an asynchronous callback to return the result.

NOTE

This API is deprecated since API version 9. Use fs.copyFile instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
src	string|number	Yes	Path or file descriptor of the file to copy.
dest	string|number	Yes	Path or file descriptor of the new file.
mode	number	No	Whether to overwrite the file with the same name in the destination directory. The default value is 0, which is the only value supported. 0: overwrite the file with the same name and truncate the part that is not overwritten.
callback	AsyncCallback<void>	Yes	Callback invoked immediately after the file is copied.

Example

import { BusinessError } from '@ohos.base';
let srcPath = pathDir + "srcDir/test.txt";
let dstPath = pathDir + "dstDir/test.txt";
fileio.copyFile(srcPath, dstPath, (err: BusinessError) => {
  // Do something.
});

fileio.copyFileSync

copyFileSync(src: string|number, dest: string|number, mode?: number): void

Copies a file. This API returns the result synchronously.

NOTE

This API is deprecated since API version 9. Use fs.copyFileSync instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
src	string|number	Yes	Path or file descriptor of the file to copy.
dest	string|number	Yes	Path or file descriptor of the new file.
mode	number	No	Whether to overwrite the file with the same name in the destination directory. The default value is 0, which is the only value supported. 0: overwrite the file with the same name and truncate the part that is not overwritten.

Example

let srcPath = pathDir + "srcDir/test.txt";
let dstPath = pathDir + "dstDir/test.txt";
fileio.copyFileSync(srcPath, dstPath);

fileio.mkdir

mkdir(path: string, mode?: number): Promise<void>

Creates a directory. This API uses a promise to return the result.

NOTE

This API is deprecated since API version 9. Use fs.mkdir instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the directory.
mode	number	No	Permission on the directory to create. You can specify multiple permissions, separated using a bitwise OR operator (|). The default value is 0o775. - 0o775: The owner has the read, write, and execute permissions, and other users have the read and execute permissions. - 0o700: The owner has the read, write, and execute permissions. - 0o400: The owner has the read permission. - 0o200: The owner has the write permission. - 0o100: The owner has the execute permission. - 0o070: The user group has the read, write, and execute permissions. - 0o040: The user group has the read permission. - 0o020: The user group has the write permission. - 0o010: The user group has the execute permission. - 0o007: Other users have the read, write, and execute permissions. - 0o004: Other users have the read permission. - 0o002: Other users have the write permission. - 0o001: Other users have the execute permission.

Return value

Type	Description
Promise<void>	Promise that returns no value.

Example

import { BusinessError } from '@ohos.base';
let dirPath = pathDir + '/testDir';
fileio.mkdir(dirPath).then(() => {
  console.info("Directory created");
}).catch((error: BusinessError) => {
  console.info("mkdir failed with error:" + error);
});

fileio.mkdir

mkdir(path: string, mode: number, callback: AsyncCallback<void>): void

Creates a directory. This API uses an asynchronous callback to return the result.

NOTE

This API is deprecated since API version 9. Use fs.mkdir instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the directory.
mode	number	No	Permission on the directory to create. You can specify multiple permissions, separated using a bitwise OR operator (|). The default value is 0o775. - 0o775: The owner has the read, write, and execute permissions, and other users have the read and execute permissions. - 0o700: The owner has the read, write, and execute permissions. - 0o400: The owner has the read permission. - 0o200: The owner has the write permission. - 0o100: The owner has the execute permission. - 0o070: The user group has the read, write, and execute permissions. - 0o040: The user group has the read permission. - 0o020: The user group has the write permission. - 0o010: The user group has the execute permission. - 0o007: Other users have the read, write, and execute permissions. - 0o004: Other users have the read permission. - 0o002: Other users have the write permission. - 0o001: Other users have the execute permission.
callback	AsyncCallback<void>	Yes	Callback invoked when the directory is created asynchronously.

Example

import { BusinessError } from '@ohos.base';
let dirPath = pathDir + '/testDir';
fileio.mkdir(dirPath, (err: BusinessError) => {
  console.info("Directory created");
});

fileio.mkdirSync

mkdirSync(path: string, mode?: number): void

Creates a directory. This API returns the result synchronously.

NOTE

This API is deprecated since API version 9. Use fs.mkdirSync instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the directory.
mode	number	No	Permission on the directory to create. You can specify multiple permissions, separated using a bitwise OR operator (|). The default value is 0o775. - 0o775: The owner has the read, write, and execute permissions, and other users have the read and execute permissions. - 0o700: The owner has the read, write, and execute permissions. - 0o400: The owner has the read permission. - 0o200: The owner has the write permission. - 0o100: The owner has the execute permission. - 0o070: The user group has the read, write, and execute permissions. - 0o040: The user group has the read permission. - 0o020: The user group has the write permission. - 0o010: The user group has the execute permission. - 0o007: Other users have the read, write, and execute permissions. - 0o004: Other users have the read permission. - 0o002: Other users have the write permission. - 0o001: Other users have the execute permission.

Example

let dirPath = path + '/testDir';
fileio.mkdirSync(dirPath);

fileio.open⁷⁺

open(path: string, flags?: number, mode?: number): Promise<number>

Opens a file. This API uses a promise to return the result.

NOTE

This API is deprecated since API version 9. Use fs.open instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the file.
flags	number	No	Option for opening the file. You must specify one of the following options. By default, the file is open in read-only mode. - 0o0: Open the file in read-only mode. - 0o1: Open the file in write-only mode. - 0o2: Open the file in read/write mode. In addition, you can specify the following options, separated using a bitwise OR operator (|). By default, no additional option is specified. - 0o100: If the file does not exist, create it. If you use this option, you must also specify mode. - 0o200: If 0o100 is added and the file already exists, throw an exception. - 0o1000: If the file exists and is open in write-only or read/write mode, truncate the file length to 0. - 0o2000: Open the file in append mode. New data will be appended to the file (added to the end of the file). - 0o4000: If path points to a named pipe (also known as a FIFO), block special file, or character special file, perform non-blocking operations on the open file and in subsequent I/Os. - 0o200000: If path does not point to a directory, throw an exception. - 0o400000: If path points to a symbolic link, throw an exception. - 0o4010000: Open the file in synchronous I/O mode.
mode	number	No	Permissions on the file. You can specify multiple permissions, separated using a bitwise OR operator (|). The default value is 0o660. - 0o660: The owner and user group have the read and write permissions. - 0o700: The owner has the read, write, and execute permissions. - 0o400: The owner has the read permission. - 0o200: The owner has the write permission. - 0o100: The owner has the execute permission. - 0o070: The user group has the read, write, and execute permissions. - 0o040: The user group has the read permission. - 0o020: The user group has the write permission. - 0o010: The user group has the execute permission. - 0o007: Other users have the read, write, and execute permissions. - 0o004: Other users have the read permission. - 0o002: Other users have the write permission. - 0o001: Other users have the execute permission.

Return value

Type	Description
Promise<number>	Promise used to return the file descriptor of the file opened.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
fileio.open(filePath, 0o1, 0o0200).then((number: number) => {
  console.info("File opened");
}).catch((err: BusinessError) => {
  console.info("open file failed with error:" + err);
});

fileio.open⁷⁺

open(path: string, flags: number, mode: number, callback: AsyncCallback<number>): void

Opens a file. This API uses an asynchronous callback to return the result.

NOTE

This API is deprecated since API version 9. Use fs.open instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the file.
flags	number	No	Option for opening the file. You must specify one of the following options. By default, the file is open in read-only mode. - 0o0: Open the file in read-only mode. - 0o1: Open the file in write-only mode. - 0o2: Open the file in read/write mode. In addition, you can specify the following options, separated using a bitwise OR operator (|). By default, no additional option is specified. - 0o100: If the file does not exist, create it. If you use this option, you must also specify mode. - 0o200: If 0o100 is added and the file already exists, throw an exception. - 0o1000: If the file exists and is open in write-only or read/write mode, truncate the file length to 0. - 0o2000: Open the file in append mode. New data will be appended to the file (added to the end of the file). - 0o4000: If path points to a named pipe (also known as a FIFO), block special file, or character special file, perform non-blocking operations on the open file and in subsequent I/Os. - 0o200000: If path does not point to a directory, throw an exception. - 0o400000: If path points to a symbolic link, throw an exception. - 0o4010000: Open the file in synchronous I/O mode.
mode	number	No	Permissions on the file. You can specify multiple permissions, separated using a bitwise OR operator (|). The default value is 0o660. - 0o660: The owner and user group have the read and write permissions. - 0o700: The owner has the read, write, and execute permissions. - 0o400: The owner has the read permission. - 0o200: The owner has the write permission. - 0o100: The owner has the execute permission. - 0o070: The user group has the read, write, and execute permissions. - 0o040: The user group has the read permission. - 0o020: The user group has the write permission. - 0o010: The user group has the execute permission. - 0o007: Other users have the read, write, and execute permissions. - 0o004: Other users have the read permission. - 0o002: Other users have the write permission. - 0o001: Other users have the execute permission.
callback	AsyncCallback<number>	Yes	Callback invoked when the file is open asynchronously.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
fileio.open(filePath, 0, (err: BusinessError, fd: number) => {
  // Do something.
});

fileio.openSync

openSync(path: string, flags?: number, mode?: number): number

Opens a file. This API returns the result synchronously.

NOTE

This API is deprecated since API version 9. Use fs.openSync instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the file.
flags	number	No	Option for opening the file. You must specify one of the following options. By default, the file is open in read-only mode. - 0o0: Open the file in read-only mode. - 0o1: Open the file in write-only mode. - 0o2: Open the file in read/write mode. In addition, you can specify the following options, separated using a bitwise OR operator (|). By default, no additional option is specified. - 0o100: If the file does not exist, create it. If you use this option, you must also specify mode. - 0o200: If 0o100 is added and the file already exists, throw an exception. - 0o1000: If the file exists and is open in write-only or read/write mode, truncate the file length to 0. - 0o2000: Open the file in append mode. New data will be appended to the file (added to the end of the file). - 0o4000: If path points to a named pipe (also known as a FIFO), block special file, or character special file, perform non-blocking operations on the open file and in subsequent I/Os. - 0o200000: If path does not point to a directory, throw an exception. - 0o400000: If path points to a symbolic link, throw an exception. - 0o4010000: Open the file in synchronous I/O mode.
mode	number	No	Permissions on the file. You can specify multiple permissions, separated using a bitwise OR operator (|). The default value is 0o660. - 0o660: The owner and user group have the read and write permissions. - 0o640: The owner has the read and write permissions, and the user group has the read permission. - 0o700: The owner has the read, write, and execute permissions. - 0o400: The owner has the read permission. - 0o200: The owner has the write permission. - 0o100: The owner has the execute permission. - 0o070: The user group has the read, write, and execute permissions. - 0o040: The user group has the read permission. - 0o020: The user group has the write permission. - 0o010: The user group has the execute permission. - 0o007: Other users have the read, write, and execute permissions. - 0o004: Other users have the read permission. - 0o002: Other users have the write permission. - 0o001: Other users have the execute permission. The file permissions on newly created files are affected by umask, which is set as the process starts. Currently, the modification of umask is not open.

Return value

Type	Description
number	File descriptor of the file opened.

Example

let filePath = pathDir + "/test.txt";
let fd = fileio.openSync(filePath, 0o102, 0o640);

let filePath = pathDir + "/test.txt";
let fd = fileio.openSync(filePath, 0o102, 0o666);
fileio.writeSync(fd, 'hello world');
let fd1 = fileio.openSync(filePath, 0o2002);
fileio.writeSync(fd1, 'hello world');
class Option {
  offset: number = 0;
  length: number = 4096;
  position: number = 0;
}
let option = new Option();
option.position = 0;
let buf = new ArrayBuffer(4096)
let num = fileio.readSync(fd1, buf, option);
console.info("num == " + num);

fileio.read

read(fd: number, buffer: ArrayBuffer, options?: { offset?: number; length?: number; position?: number; }): Promise<ReadOut>

Reads data from a file. This API uses a promise to return the result.

NOTE

This API is deprecated since API version 9. Use fs.read instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
fd	number	Yes	File descriptor of the file to read.
buffer	ArrayBuffer	Yes	Buffer used to store the file data read.
options	Object	No	The options are as follows: - offset (number): position to store the data read in the buffer in reference to the start address of the buffer. The default value is 0. - length (number): length of the data to read. The default value is the buffer length minus the offset. - position (number): position of the data to read in the file. This parameter is optional. By default, data is read from the current position. Constraints: offset + length <= Buffer size

Return value

Type	Description
Promise<ReadOut>	Promise used to return the data read.

Example

import { BusinessError } from '@ohos.base';
import buffer from '@ohos.buffer';
let filePath = pathDir + "/test.txt";
let fd = fileio.openSync(filePath, 0o2);
let arrayBuffer = new ArrayBuffer(4096);
fileio.read(fd, arrayBuffer).then((readLen: number) => {
  console.info("Read file data successfully");
  let buf = buffer.from(arrayBuffer, 0, readLen);
  console.log(`The content of file: ${buf.toString()}`);
}).catch((err: BusinessError) => {
  console.info("read file data failed with error:" + err);
});

fileio.read

read(fd: number, buffer: ArrayBuffer, options: { offset?: number; length?: number; position?: number; }, callback: AsyncCallback<ReadOut>): void

Reads data from a file. This API uses an asynchronous callback to return the result.

NOTE

This API is deprecated since API version 9. Use fs.read instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
fd	number	Yes	File descriptor of the file to read.
buffer	ArrayBuffer	Yes	Buffer used to store the file data read.
options	Object	No	The options are as follows: - offset (number): position to store the data read in the buffer in reference to the start address of the buffer. The default value is 0. - length (number): length of the data to read. The default value is the buffer length minus the offset. - position (number): position of the data to read in the file. This parameter is optional. By default, data is read from the current position. Constraints: offset + length <= Buffer size
callback	AsyncCallback<ReadOut>	Yes	Callback invoked when the data is read asynchronously.

Example

import { BusinessError } from '@ohos.base';
import buffer from '@ohos.buffer';
let filePath = pathDir + "/test.txt";
let fd = fileio.openSync(filePath, 0o2);
let arrayBuffer = new ArrayBuffer(4096);
fileio.read(fd, arrayBuffer, (err: BusinessError, readLen: number) => {
  if (readLen) {
    console.info("Read file data successfully");
    let buf = buffer.from(arrayBuffer, 0, readLen);
    console.info(`The content of file: ${buf.toString()}`);
  }
});

fileio.readSync

readSync(fd: number, buffer: ArrayBuffer, options?: { offset?: number; length?: number; position?: number; }): number

Reads data from a file. This API returns the result synchronously.

NOTE

This API is deprecated since API version 9. Use fs.readSync instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
fd	number	Yes	File descriptor of the file to read.
buffer	ArrayBuffer	Yes	Buffer used to store the file data read.
options	Object	No	The options are as follows: - offset (number): position to store the data read in the buffer in reference to the start address of the buffer. The default value is 0. - length (number): length of the data to read. The default value is the buffer length minus the offset. - position (number): position of the data to read in the file. This parameter is optional. By default, data is read from the current position. Constraints: offset + length <= Buffer size

Return value

Type	Description
number	Length of the data read.

Example

let filePath = pathDir + "/test.txt";
let fd = fileio.openSync(filePath, 0o2);
let buf = new ArrayBuffer(4096);
let num = fileio.readSync(fd, buf);

fileio.rmdir⁷⁺

rmdir(path: string): Promise<void>

Deletes a directory. This API uses a promise to return the result.

NOTE

This API is deprecated since API version 9. Use fs.rmdir instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the directory.

Return value

Type	Description
Promise<void>	Promise that returns no value.

Example

import { BusinessError } from '@ohos.base';
let dirPath = pathDir + '/testDir';
fileio.rmdir(dirPath).then(() => {
  console.info("Directory deleted");
}).catch((err: BusinessError) => {
  console.info("rmdir failed with error:" + err);
});

fileio.rmdir⁷⁺

rmdir(path: string, callback: AsyncCallback<void>): void

Deletes a directory. This API uses an asynchronous callback to return the result.

NOTE

This API is deprecated since API version 9. Use fs.rmdir instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the directory.
callback	AsyncCallback<void>	Yes	Callback invoked when the directory is deleted asynchronously.

Example

import { BusinessError } from '@ohos.base';
let dirPath = pathDir + '/testDir';
fileio.rmdir(dirPath, (err: BusinessError) => {
  // Do something.
  console.info("Directory deleted");
});

fileio.rmdirSync⁷⁺

rmdirSync(path: string): void

Deletes a directory. This API returns the result synchronously.

NOTE

This API is deprecated since API version 9. Use fs.rmdirSync instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the directory.

Example

let dirPath = pathDir + '/testDir';
fileio.rmdirSync(dirPath);

fileio.unlink

unlink(path: string): Promise<void>

Deletes a file. This API uses a promise to return the result.

NOTE

This API is deprecated since API version 9. Use fs.unlink instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the file.

Return value

Type	Description
Promise<void>	Promise that returns no value.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
fileio.unlink(filePath).then(() => {
  console.info("File deleted");
}).catch((error: BusinessError) => {
  console.info("remove file failed with error:" + error);
});

fileio.unlink

unlink(path: string, callback: AsyncCallback<void>): void

Deletes a file. This API uses an asynchronous callback to return the result.

NOTE

This API is deprecated since API version 9. Use fs.unlink instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the file.
callback	AsyncCallback<void>	Yes	Callback invoked immediately after the file is deleted.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
fileio.unlink(filePath, (err: BusinessError) => {
  console.info("File deleted");
});

fileio.unlinkSync

unlinkSync(path: string): void

Deletes a file. This API returns the result synchronously.

NOTE

This API is deprecated since API version 9. Use fs.unlinkSync instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the file.

Example

let filePath = pathDir + "/test.txt";
fileio.unlinkSync(filePath);

fileio.write

write(fd: number, buffer: ArrayBuffer|string, options?: { offset?: number; length?: number; position?: number; encoding?: string; }): Promise<number>

Writes data into a file. This API uses a promise to return the result.

NOTE

This API is deprecated since API version 9. Use fs.write instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
fd	number	Yes	File descriptor of the file to write.
buffer	ArrayBuffer|string	Yes	Data to write. It can be a string or data from a buffer.
options	Object	No	The options are as follows: - offset (number): position of the data to write in reference to the start address of the data. The default value is 0. - length (number): length of the data to write. The default value is the buffer length minus the offset. - position (number): start position to write the data in the file. This parameter is optional. By default, data is written from the current position. - encoding (string): format of the data to be encoded when the data is a string. The default value is utf-8, which is the only value supported. Constraints: offset + length <= Buffer size

Return value

Type	Description
Promise<number>	Promise used to return the length of the data written.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
let fd = fileio.openSync(filePath, 0o100|0o2, 0o666);
fileio.write(fd, "hello, world").then((number: number) => {
  console.info("write data to file succeed and size is:" + number);
}).catch((err: BusinessError) => {
  console.info("write data to file failed with error:" + err);
});

fileio.write

write(fd: number, buffer: ArrayBuffer|string, options: { offset?: number; length?: number; position?: number; encoding?: string; }, callback: AsyncCallback<number>): void

Writes data into a file. This API uses an asynchronous callback to return the result.

NOTE

This API is deprecated since API version 9. Use fs.write instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
fd	number	Yes	File descriptor of the file to write.
buffer	ArrayBuffer|string	Yes	Data to write. It can be a string or data from a buffer.
options	Object	No	The options are as follows: - offset (number): position of the data to write in reference to the start address of the data. The default value is 0. - length (number): length of the data to write. The default value is the buffer length minus the offset. - position (number): start position to write the data in the file. This parameter is optional. By default, data is written from the current position. - encoding (string): format of the data to be encoded when the data is a string. The default value is utf-8, which is the only value supported. Constraints: offset + length <= Buffer size
callback	AsyncCallback<number>	Yes	Callback invoked when the data is written asynchronously.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
let fd = fileio.openSync(filePath, 0o100|0o2, 0o666);
fileio.write(fd, "hello, world", (err: BusinessError, bytesWritten: number) => {
  if (bytesWritten) {
    console.info("write data to file succeed and size is:" + bytesWritten);
  }
});

fileio.writeSync

writeSync(fd: number, buffer: ArrayBuffer|string, options?: { offset?: number; length?: number; position?: number; encoding?: string; }): number

Writes data into a file. This API returns the result synchronously.

NOTE

This API is deprecated since API version 9. Use fs.writeSync instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
fd	number	Yes	File descriptor of the file to write.
buffer	ArrayBuffer|string	Yes	Data to write. It can be a string or data from a buffer.
options	Object	No	The options are as follows: - offset (number): position of the data to write in reference to the start address of the data. The default value is 0. - length (number): length of the data to write. The default value is the buffer length minus the offset. - position (number): start position to write the data in the file. This parameter is optional. By default, data is written from the current position. - encoding (string): format of the data to be encoded when the data is a string. The default value is utf-8, which is the only value supported. Constraints: offset + length <= Buffer size

Return value

Type	Description
number	Length of the data written in the file.

Example

let filePath = pathDir + "/test.txt";
let fd = fileio.openSync(filePath, 0o100|0o2, 0o666);
let num = fileio.writeSync(fd, "hello, world");

fileio.hash

hash(path: string, algorithm: string): Promise<string>

Calculates the hash value of a file. This API uses a promise to return the result.

NOTE

This API is deprecated since API version 9. Use hash.write instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the file.
algorithm	string	Yes	Algorithm used to calculate the hash value. The value can be md5, sha1, or sha256. sha256 is recommended for security purposes.

Return value

Type	Description
Promise<string>	Promise used to return the hash value obtained. The hash value is a hexadecimal string consisting of digits and uppercase letters.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
fileio.hash(filePath, "sha256").then((str: string) => {
  console.info("calculate file hash succeed:" + str);
}).catch((err: BusinessError) => {
  console.info("calculate file hash failed with error:" + err);
});

fileio.hash

hash(path: string, algorithm: string, callback: AsyncCallback<string>): void

Calculates the hash value of a file. This API uses an asynchronous callback to return the result.

NOTE

This API is deprecated since API version 9. Use hash.write instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the file.
algorithm	string	Yes	Algorithm used to calculate the hash value. The value can be md5, sha1, or sha256. sha256 is recommended for security purposes.
callback	AsyncCallback<string>	Yes	Callback used to return the hash value obtained. The hash value is a hexadecimal string consisting of digits and uppercase letters.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
fileio.hash(filePath, "sha256", (err: BusinessError, hashStr: string) => {
  if (hashStr) {
    console.info("calculate file hash succeed:" + hashStr);
  }
});

fileio.chmod⁷⁺

chmod(path: string, mode: number): Promise<void>

Changes file permissions. This API uses a promise to return the result.

NOTE

This API is deprecated since API version 9.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the file.
mode	number	Yes	Permissions on the file. You can specify multiple permissions, separated using a bitwise OR operator (|). - 0o700: The owner has the read, write, and execute permissions. - 0o400: The owner has the read permission. - 0o200: The owner has the write permission. - 0o100: The owner has the execute permission. - 0o070: The user group has the read, write, and execute permissions. - 0o040: The user group has the read permission. - 0o020: The user group has the write permission. - 0o010: The user group has the execute permission. - 0o007: Other users have the read, write, and execute permissions. - 0o004: Other users have the read permission. - 0o002: Other users have the write permission. - 0o001: Other users have the execute permission.

Return value

Type	Description
Promise<void>	Promise that returns no value.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
fileio.chmod(filePath, 0o700).then(() => {
  console.info("File permissions changed");
}).catch((err: BusinessError) => {
  console.info("chmod failed with error:" + err);
});

fileio.chmod⁷⁺

chmod(path: string, mode: number, callback: AsyncCallback<void>): void

Changes file permissions. This API uses an asynchronous callback to return the result.

NOTE

This API is deprecated since API version 9.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the file.
mode	number	Yes	Permissions on the file. You can specify multiple permissions, separated using a bitwise OR operator (|). - 0o700: The owner has the read, write, and execute permissions. - 0o400: The owner has the read permission. - 0o200: The owner has the write permission. - 0o100: The owner has the execute permission. - 0o070: The user group has the read, write, and execute permissions. - 0o040: The user group has the read permission. - 0o020: The user group has the write permission. - 0o010: The user group has the execute permission. - 0o007: Other users have the read, write, and execute permissions. - 0o004: Other users have the read permission. - 0o002: Other users have the write permission. - 0o001: Other users have the execute permission.
callback	AsyncCallback<void>	Yes	Callback invoked when the file permissions are changed asynchronously.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
fileio.chmod(filePath, 0o700, (err: BusinessError) => {
  // Do something.
});

fileio.chmodSync⁷⁺

chmodSync(path: string, mode: number): void

Changes file permissions. This API returns the result synchronously.

NOTE

This API is deprecated since API version 9.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the file.
mode	number	Yes	Permissions on the file. You can specify multiple permissions, separated using a bitwise OR operator (|). - 0o700: The owner has the read, write, and execute permissions. - 0o400: The owner has the read permission. - 0o200: The owner has the write permission. - 0o100: The owner has the execute permission. - 0o070: The user group has the read, write, and execute permissions. - 0o040: The user group has the read permission. - 0o020: The user group has the write permission. - 0o010: The user group has the execute permission. - 0o007: Other users have the read, write, and execute permissions. - 0o004: Other users have the read permission. - 0o002: Other users have the write permission. - 0o001: Other users have the execute permission.

Example

let filePath = pathDir + "/test.txt";
fileio.chmodSync(filePath, 0o700);

fileio.fstat⁷⁺

fstat(fd: number): Promise<Stat>

Obtains file information based on the file descriptor. This API uses a promise to return the result.

NOTE

This API is deprecated since API version 9. Use fs.stat instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
fd	number	Yes	File descriptor of the target file.

Return value

Type	Description
Promise<Stat>	Promise used to return the file information obtained.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
let fd = fileio.openSync(filePath);
fileio.fstat(fd).then((stat: fileio.Stat) => {
  console.info("fstat succeed, the size of file is " + stat.size);
}).catch((err: BusinessError) => {
  console.info("fstat failed with error:" + err);
});

fileio.fstat⁷⁺

fstat(fd: number, callback: AsyncCallback<Stat>): void

Obtains file information based on the file descriptor. This API uses an asynchronous callback to return the result.

NOTE

This API is deprecated since API version 9. Use fs.stat instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
fd	number	Yes	File descriptor of the target file.
callback	AsyncCallback<Stat>	Yes	Callback invoked to return the file information obtained.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
let fd = fileio.openSync(filePath);
fileio.fstat(fd, (err: BusinessError) => {
  // Do something.
});

fileio.fstatSync⁷⁺

fstatSync(fd: number): Stat

Obtains file status information based on the file descriptor. This API returns the result synchronously.

NOTE

This API is deprecated since API version 9. Use fs.statSync instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
fd	number	Yes	File descriptor of the target file.

Return value

Type	Description
Stat	File information obtained.

Example

let filePath = pathDir + "/test.txt";
let fd = fileio.openSync(filePath);
let stat = fileio.fstatSync(fd);

fileio.ftruncate⁷⁺

ftruncate(fd: number, len?: number): Promise<void>

Truncates a file based on the file descriptor. This API uses a promise to return the result.

NOTE

This API is deprecated since API version 9. Use fs.truncate instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
fd	number	Yes	File descriptor of the file to truncate.
len	number	No	File length, in bytes, after truncation.

Return value

Type	Description
Promise<void>	Promise that returns no value.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
let fd = fileio.openSync(filePath);
fileio.ftruncate(fd, 5).then((err: BusinessError) => {
  console.info("File truncated");
}).catch((err: BusinessError) => {
  console.info("truncate file failed with error:" + err);
});

fileio.ftruncate⁷⁺

ftruncate(fd: number, len?: number, callback: AsyncCallback<void>): void

Truncates a file based on the file descriptor. This API uses an asynchronous callback to return the result.

NOTE

This API is deprecated since API version 9. Use fs.truncate instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
fd	number	Yes	File descriptor of the file to truncate.
len	number	No	File length, in bytes, after truncation.
callback	AsyncCallback<void>	Yes	Callback that returns no value.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
let fd = fileio.openSync(filePath);
let len = 5;
fileio.ftruncate(fd, 5, (err: BusinessError) => {
  // Do something.
});

fileio.ftruncateSync⁷⁺

ftruncateSync(fd: number, len?: number): void

Truncates a file based on the file descriptor. This API returns the result synchronously.

NOTE

This API is deprecated since API version 9. Use fs.truncateSync instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
fd	number	Yes	File descriptor of the file to truncate.
len	number	No	File length, in bytes, after truncation.

Example

let filePath = pathDir + "/test.txt";
let fd = fileio.openSync(filePath);
let len = 5;
fileio.ftruncateSync(fd, len);

fileio.truncate⁷⁺

truncate(path: string, len?: number): Promise<void>

Truncates a file based on the file path. This API uses a promise to return the result.

NOTE

This API is deprecated since API version 9. Use fs.truncate instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the file to truncate.
len	number	No	File length, in bytes, after truncation.

Return value

Type	Description
Promise<void>	Promise that returns no value.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
let len = 5;
fileio.truncate(filePath, len).then(() => {
  console.info("File truncated");
}).catch((err: BusinessError) => {
  console.info("truncate file failed with error:" + err);
});

fileio.truncate⁷⁺

truncate(path: string, len?: number, callback: AsyncCallback<void>): void

Truncates a file based on the file path. This API uses an asynchronous callback to return the result.

NOTE

This API is deprecated since API version 9. Use fs.truncate instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the file to truncate.
len	number	No	File length, in bytes, after truncation.
callback	AsyncCallback<void>	Yes	Callback that returns no value.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
let len = 5;
fileio.truncate(filePath, len, (err: BusinessError) => {
  // Do something.
});

fileio.truncateSync⁷⁺

truncateSync(path: string, len?: number): void

Truncates a file based on the file path. This API returns the result synchronously.

NOTE

This API is deprecated since API version 9. Use fs.truncateSync instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the file to truncate.
len	number	No	File length, in bytes, after truncation.

Example

let filePath = pathDir + "/test.txt";
let len = 5;
fileio.truncateSync(filePath, len);

fileio.readText⁷⁺

readText(filePath: string, options?: { position?: number; length?: number; encoding?: string; }): Promise<string>

Reads the text content of a file. This API uses a promise to return the result.

NOTE

This API is deprecated since API version 9. Use fs.readText instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
filePath	string	Yes	Application sandbox path of the file to read.
options	Object	No	The options are as follows: - position (number): position of the data to read in the file. This parameter is optional. By default, data is read from the current position. - length (number): length of the data to read. The default value is the buffer length minus the offset. - encoding (string): format of the data (string) to be encoded. The default value is utf-8, which is the only value supported.

Return value

Type	Description
Promise<string>	Promise used to return the file content read.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
fileio.readText(filePath).then((str: string) => {
  console.info("readText succeed:" + str);
}).catch((err: BusinessError) => {
  console.info("readText failed with error:" + err);
});

fileio.readText⁷⁺

readText(filePath: string, options: { position?: number; length?: number; encoding?: string; }, callback: AsyncCallback<string>): void

Reads the text content of a file. This API uses an asynchronous callback to return the result.

NOTE

This API is deprecated since API version 9. Use fs.readText instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
filePath	string	Yes	Application sandbox path of the file to read.
options	Object	No	The options are as follows: - position (number): position of the data to read in the file. This parameter is optional. By default, data is read from the current position. - length (number): length of the data to read. The default value is the buffer length minus the offset. - encoding: format of the data to be encoded. The default value is utf-8, which is the only value supported.
callback	AsyncCallback<string>	Yes	Callback invoked to return the content read.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
class Option {
  length: number = 4096;
  position: number = 0;
  encoding: string = 'utf-8';
}
let option = new Option();
option.position = 1;
option.encoding = 'utf-8';
fileio.readText(filePath, option, (err: BusinessError, str: string) => {
  // Do something.
});

fileio.readTextSync⁷⁺

readTextSync(filePath: string, options?: { position?: number; length?: number; encoding?: string; }): string

Reads the text of a file. This API returns the result synchronously.

NOTE

This API is deprecated since API version 9. Use fs.readTextSync instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
filePath	string	Yes	Application sandbox path of the file to read.
options	Object	No	The options are as follows: - position (number): position of the data to read in the file. This parameter is optional. By default, data is read from the current position. - length (number): length of the data to read. The default value is the buffer length minus the offset. - encoding (string): format of the data (string) to be encoded. The default value is utf-8, which is the only value supported.

Return value

Type	Description
string	File content read.

Example

let filePath = pathDir + "/test.txt";
class Option {
  length: number = 4096;
  position: number = 0;
  encoding: string = 'utf-8';
}
let option = new Option();
option.position = 1;
option.length = 3;
let str = fileio.readTextSync(filePath, option);

fileio.lstat⁷⁺

lstat(path: string): Promise<Stat>

Obtains link information. This API uses a promise to return the result.

NOTE

This API is deprecated since API version 9. Use fs.lstat instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the target file.

Return value

Type	Description
Promise<Stat>	Promise used to return the symbolic link information obtained. For details, see stat.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
fileio.lstat(filePath).then((stat: fileio.Stat) => {
  console.info("get link status succeed, the size of file is" + stat.size);
}).catch((err: BusinessError) => {
  console.info("get link status failed with error:" + err);
});

fileio.lstat⁷⁺

lstat(path: string, callback: AsyncCallback<Stat>): void

Obtains link information. This API uses an asynchronous callback to return the result.

NOTE

This API is deprecated since API version 9. Use fs.lstat instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the target file.
callback	AsyncCallback<Stat>	Yes	Callback invoked to return the symbolic link information obtained.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
fileio.lstat(filePath, (err: BusinessError, stat: fileio.Stat) => {
  // Do something.
});

fileio.lstatSync⁷⁺

lstatSync(path: string): Stat

Obtains the link information. This API returns the result synchronously.

NOTE

This API is deprecated since API version 9. Use fs.lstatSync instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the target file.

Return value

Type	Description
Stat	Link information obtained.

Example

let filePath = pathDir + "/test.txt";
let stat = fileio.lstatSync(filePath);

fileio.rename⁷⁺

rename(oldPath: string, newPath: string): Promise<void>

Renames a file. This API uses a promise to return the result.

NOTE

This API is deprecated since API version 9. Use fs.rename instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
oldPath	string	Yes	Application sandbox path of the file to rename.
newPath	string	Yes	Application sandbox path of the file renamed.

Return value

Type	Description
Promise<void>	Promise that returns no value.

Example

import { BusinessError } from '@ohos.base';
let srcFile = pathDir + "/test.txt";
let dstFile = pathDir + '/new.txt';
fileio.rename(srcFile, dstFile).then(() => {
  console.info("File renamed");
}).catch((err: BusinessError) => {
  console.info("rename failed with error:" + err);
});

fileio.rename⁷⁺

rename(oldPath: string, newPath: string, callback: AsyncCallback<void>): void

Renames a file. This API uses an asynchronous callback to return the result.

NOTE

This API is deprecated since API version 9. Use fs.rename instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
oldPath	string	Yes	Application sandbox path of the file to rename.
newPath	string	Yes	Application sandbox path of the file renamed.
callback	AsyncCallback<void>	Yes	Callback invoked when the file is asynchronously renamed.

Example

import { BusinessError } from '@ohos.base';
let srcFile = pathDir + "/test.txt";
let dstFile = pathDir + '/new.txt';
fileio.rename(srcFile, dstFile, (err: BusinessError) => {
});

fileio.renameSync⁷⁺

renameSync(oldPath: string, newPath: string): void

Renames a file. This API returns the result synchronously.

NOTE

This API is deprecated since API version 9. Use fs.renameSync instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
oldPath	string	Yes	Application sandbox path of the file to rename.
newPath	string	Yes	Application sandbox path of the file renamed.

Example

let srcFile = pathDir + "/test.txt";
let dstFile = pathDir + '/new.txt';
fileio.renameSync(srcFile, dstFile);

fileio.fsync⁷⁺

fsync(fd: number): Promise<void>

Flushes data of a file to disk. This API uses a promise to return the result.

NOTE

This API is deprecated since API version 9. Use fs.fsync instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
fd	number	Yes	File descriptor of the file to flush.

Return value

Type	Description
Promise<void>	Promise that returns no value.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
let fd = fileio.openSync(filePath);
fileio.fsync(fd).then(() => {
  console.info("Data flushed");
}).catch((err: BusinessError) => {
  console.info("sync data failed with error:" + err);
});

fileio.fsync⁷⁺

fsync(fd: number, callback: AsyncCallback<void>): void

Flushes data of a file to disk. This API uses an asynchronous callback to return the result.

NOTE

This API is deprecated since API version 9. Use fs.fsync instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
fd	number	Yes	File descriptor of the file to flush.
Callback	AsyncCallback<void>	Yes	Callback invoked when the file data is synchronized in asynchronous mode.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
let fd = fileio.openSync(filePath);
fileio.fsync(fd, (err: BusinessError) => {
  // Do something.
});

fileio.fsyncSync⁷⁺

fsyncSync(fd: number): void

Flushes data of a file to disk synchronously.

NOTE

This API is deprecated since API version 9. Use fs.fsyncSync instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
fd	number	Yes	File descriptor of the file to flush.

Example

let filePath = pathDir + "/test.txt";
let fd = fileio.openSync(filePath);
fileio.fsyncSync(fd);

fileio.fdatasync⁷⁺

fdatasync(fd: number): Promise<void>

Flushes data of a file to disk. This API uses a promise to return the result. fdatasync() is similar to fsync(), but does not flush modified metadata unless that metadata is needed.

NOTE

This API is deprecated since API version 9. Use fs.fdatasync instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
fd	number	Yes	File descriptor of the file to flush.

Return value

Type	Description
Promise<void>	Promise that returns no value.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
let fd = fileio.openSync(filePath);
fileio.fdatasync(fd).then((err: BusinessError) => {
  console.info("Data flushed");
}).catch((err: BusinessError) => {
  console.info("sync data failed with error:" + err);
});

fileio.fdatasync⁷⁺

fdatasync(fd: number, callback: AsyncCallback<void>): void

Flushes data of a file to disk. This API uses an asynchronous callback to return the result.

NOTE

This API is deprecated since API version 9. Use fs.fdatasync instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
fd	number	Yes	File descriptor of the file to synchronize.
callback	AsyncCallback<void>	Yes	Callback invoked when the file data is synchronized in asynchronous mode.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
let fd = fileio.openSync(filePath);
fileio.fdatasync (fd, (err: BusinessError) => {
  // Do something.
});

fileio.fdatasyncSync⁷⁺

fdatasyncSync(fd: number): void

Synchronizes data in a file synchronously.

NOTE

This API is deprecated since API version 9. Use fs.fdatasyncSync instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
fd	number	Yes	File descriptor of the file to flush.

Example

let filePath = pathDir + "/test.txt";
let fd = fileio.openSync(filePath);
let stat = fileio.fdatasyncSync(fd);

fileio.symlink⁷⁺

symlink(target: string, srcPath: string): Promise<void>

Creates a symbolic link based on the file path. This API uses a promise to return the result.

NOTE

This API is deprecated since API version 9. Use fs.symlink instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
target	string	Yes	Application sandbox path of the target file.
srcPath	string	Yes	Application sandbox path of the symbolic link.

Return value

Type	Description
Promise<void>	Promise that returns no value.

Example

import { BusinessError } from '@ohos.base';
let srcFile = pathDir + "/test.txt";
let dstFile = pathDir + '/test';
fileio.symlink(srcFile, dstFile).then(() => {
  console.info("Symbolic link created");
}).catch((err: BusinessError) => {
  console.info("symlink failed with error:" + err);
});

fileio.symlink⁷⁺

symlink(target: string, srcPath: string, callback: AsyncCallback<void>): void

Creates a symbolic link based on the file path. This API uses an asynchronous callback to return the result.

NOTE

This API is deprecated since API version 9. Use fs.symlink instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
target	string	Yes	Application sandbox path of the target file.
srcPath	string	Yes	Application sandbox path of the symbolic link.
callback	AsyncCallback<void>	Yes	Callback invoked when the symbolic link is created asynchronously.

Example

import { BusinessError } from '@ohos.base';
let srcFile = pathDir + "/test.txt";
let dstFile = pathDir + '/test';
fileio.symlink(srcFile, dstFile, (err: BusinessError) => {
  // Do something.
});

fileio.symlinkSync⁷⁺

symlinkSync(target: string, srcPath: string): void

Creates a symbolic link based on a file path. This API returns the result synchronously.

NOTE

This API is deprecated since API version 9. Use fs.symlinkSync instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
target	string	Yes	Application sandbox path of the target file.
srcPath	string	Yes	Application sandbox path of the symbolic link.

Example

let srcFile = pathDir + "/test.txt";
let dstFile = pathDir + '/test';
fileio.symlinkSync(srcFile, dstFile);

fileio.chown⁷⁺

chown(path: string, uid: number, gid: number): Promise<void>

Changes the file owner based on the file path. This API uses a promise to return the result.

NOTE

This API is deprecated since API version 9.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the file.
uid	number	Yes	New user ID (UID).
gid	number	Yes	New group ID (GID).

Return value

Type	Description
Promise<void>	Promise that returns no value.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
let stat = fileio.statSync(filePath);
fileio.chown(filePath, stat.uid, stat.gid).then(() => {
  console.info("File owner changed");
}).catch((err: BusinessError) => {
  console.info("chown failed with error:" + err);
});

fileio.chown⁷⁺

chown(path: string, uid: number, gid: number, callback: AsyncCallback<void>): void

Changes the file owner based on the file path. This API uses an asynchronous callback to return the result.

NOTE

This API is deprecated since API version 9.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the file.
uid	number	Yes	New UID.
gid	number	Yes	New GID.
callback	AsyncCallback<void>	Yes	Callback invoked when the file owner is changed asynchronously.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
let stat = fileio.statSync(filePath)
fileio.chown(filePath, stat.uid, stat.gid, (err: BusinessError) => {
  // Do something.
});

fileio.chownSync⁷⁺

chownSync(path: string, uid: number, gid: number): void

Changes the file owner based on its path. This API returns the result synchronously.

NOTE

This API is deprecated since API version 9.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the file.
uid	number	Yes	New UID.
gid	number	Yes	New GID.

Example

let filePath = pathDir + "/test.txt";
let stat = fileio.statSync(filePath)
fileio.chownSync(filePath, stat.uid, stat.gid);

fileio.mkdtemp⁷⁺

mkdtemp(prefix: string): Promise<string>

Creates a temporary directory. This API uses a promise to return the result.

NOTE

This API is deprecated since API version 9. Use fs.mkdtemp instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
prefix	string	Yes	A randomly generated string used to replace "XXXXXX" in a directory.

Return value

Type	Description
Promise<string>	Promise used to return the unique directory generated.

Example

import { BusinessError } from '@ohos.base';
fileio.mkdtemp(pathDir + "/XXXXXX").then((pathDir: string) => {
  console.info("mkdtemp succeed:" + pathDir);
}).catch((err: BusinessError) => {
  console.info("mkdtemp failed with error:" + err);
});

fileio.mkdtemp⁷⁺

mkdtemp(prefix: string, callback: AsyncCallback<string>): void

Creates a temporary directory. This API uses an asynchronous callback to return the result.

NOTE

This API is deprecated since API version 9. Use fs.mkdtemp instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
prefix	string	Yes	A randomly generated string used to replace "XXXXXX" in a directory.
callback	AsyncCallback<string>	Yes	Callback invoked when a temporary directory is created asynchronously.

Example

import { BusinessError } from '@ohos.base';
fileio.mkdtemp(pathDir + "/XXXXXX", (err: BusinessError, res: string) {
  // Do something.
});

fileio.mkdtempSync⁷⁺

mkdtempSync(prefix: string): string

Creates a temporary directory. This API returns the result synchronously.

NOTE

This API is deprecated since API version 9. Use fs.mkdtempSync instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
prefix	string	Yes	A randomly generated string used to replace "XXXXXX" in a directory.

Return value

Type	Description
string	Unique path generated.

Example

let res = fileio.mkdtempSync(pathDir + "/XXXXXX");

fileio.fchmod⁷⁺

fchmod(fd: number, mode: number): Promise<void>

Changes file permissions based on the file descriptor. This API uses a promise to return the result.

NOTE

This API is deprecated since API version 9.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
fd	number	Yes	File descriptor of the target file.
mode	number	Yes	Permissions on the file. You can specify multiple permissions, separated using a bitwise OR operator (|). - 0o700: The owner has the read, write, and execute permissions. - 0o400: The owner has the read permission. - 0o200: The owner has the write permission. - 0o100: The owner has the execute permission. - 0o070: The user group has the read, write, and execute permissions. - 0o040: The user group has the read permission. - 0o020: The user group has the write permission. - 0o010: The user group has the execute permission. - 0o007: Other users have the read, write, and execute permissions. - 0o004: Other users have the read permission. - 0o002: Other users have the write permission. - 0o001: Other users have the execute permission.

Return value

Type	Description
Promise<void>	Promise that returns no value.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
let fd = fileio.openSync(filePath);
let mode: number = 0o700;
fileio.fchmod(fd, mode).then(() => {
  console.info("File permissions changed");
}).catch((err: BusinessError) => {
  console.info("chmod failed with error:" + err);
});

fileio.fchmod⁷⁺

fchmod(fd: number, mode: number, callback: AsyncCallback<void>): void

Changes file permissions based on the file descriptor. This API uses an asynchronous callback to return the result.

NOTE

This API is deprecated since API version 9.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
fd	number	Yes	File descriptor of the target file.
mode	number	Yes	Permissions on the file. You can specify multiple permissions, separated using a bitwise OR operator (|). - 0o700: The owner has the read, write, and execute permissions. - 0o400: The owner has the read permission. - 0o200: The owner has the write permission. - 0o100: The owner has the execute permission. - 0o070: The user group has the read, write, and execute permissions. - 0o040: The user group has the read permission. - 0o020: The user group has the write permission. - 0o010: The user group has the execute permission. - 0o007: Other users have the read, write, and execute permissions. - 0o004: Other users have the read permission. - 0o002: Other users have the write permission. - 0o001: Other users have the execute permission.
callback	AsyncCallback<void>	Yes	Callback invoked when the file permissions are changed asynchronously.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
let fd = fileio.openSync(filePath);
let mode: number = 0o700;
fileio.fchmod(fd, mode, (err: BusinessError) => {
  // Do something.
});

fileio.fchmodSync⁷⁺

fchmodSync(fd: number, mode: number): void

Changes the file permissions based on the file descriptor. This API returns the result synchronously.

NOTE

This API is deprecated since API version 9.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
fd	number	Yes	File descriptor of the target file.
mode	number	Yes	Permissions on the file. You can specify multiple permissions, separated using a bitwise OR operator (|). - 0o700: The owner has the read, write, and execute permissions. - 0o400: The owner has the read permission. - 0o200: The owner has the write permission. - 0o100: The owner has the execute permission. - 0o070: The user group has the read, write, and execute permissions. - 0o040: The user group has the read permission. - 0o020: The user group has the write permission. - 0o010: The user group has the execute permission. - 0o007: Other users have the read, write, and execute permissions. - 0o004: Other users have the read permission. - 0o002: Other users have the write permission. - 0o001: Other users have the execute permission.

Example

let filePath = pathDir + "/test.txt";
let fd = fileio.openSync(filePath);
let mode: number = 0o700;
fileio.fchmodSync(fd, mode);

fileio.createStream⁷⁺

createStream(path: string, mode: string): Promise<Stream>

Creates a stream based on the file path. This API uses a promise to return the result.

NOTE

This API is deprecated since API version 9. Use fs.createStream instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the file.
mode	string	Yes	- r: Open a file for reading. The file must exist. - r+: Open a file for both reading and writing. The file must exist. - w: Open a file for writing. If the file exists, clear its content. If the file does not exist, create a file. - w+: Open a file for both reading and writing. If the file exists, clear its content. If the file does not exist, create a file. - a: Open a file in append mode for writing at the end of the file. If the file does not exist, create a file. If the file exists, write data to the end of the file (the original content of the file is reserved). - a+: Open a file in append mode for reading or updating at the end of the file. If the file does not exist, create a file. If the file exists, write data to the end of the file (the original content of the file is reserved).

Return value

Type	Description
Promise<Stream>	Promise used to return the stream opened.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
fileio.createStream(filePath, "r+").then((stream: fileio.Stream) => {
  console.info("Stream created");
}).catch((err: BusinessError) => {
  console.info("createStream failed with error:" + err);
});

fileio.createStream⁷⁺

createStream(path: string, mode: string, callback: AsyncCallback<Stream>): void

Creates a stream based on the file path. This API uses an asynchronous callback to return the result.

NOTE

This API is deprecated since API version 9. Use fs.createStream instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the file.
mode	string	Yes	- r: Open a file for reading. The file must exist. - r+: Open a file for both reading and writing. The file must exist. - w: Open a file for writing. If the file exists, clear its content. If the file does not exist, create a file. - w+: Open a file for both reading and writing. If the file exists, clear its content. If the file does not exist, create a file. - a: Open a file in append mode for writing at the end of the file. If the file does not exist, create a file. If the file exists, write data to the end of the file (the original content of the file is reserved). - a+: Open a file in append mode for reading or updating at the end of the file. If the file does not exist, create a file. If the file exists, write data to the end of the file (the original content of the file is reserved).
callback	AsyncCallback<Stream>	Yes	Callback invoked when the stream is created asynchronously.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
fileio.createStream(filePath, "r+", (err: BusinessError, stream: fileio.Stream) {
  // Do something.
});

fileio.createStreamSync⁷⁺

createStreamSync(path: string, mode: string): Stream

Creates a stream based on the file path. This API returns the result synchronously.

NOTE

This API is deprecated since API version 9. Use fs.createStreamSync instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the file.
mode	string	Yes	- r: Open a file for reading. The file must exist. - r+: Open a file for both reading and writing. The file must exist. - w: Open a file for writing. If the file exists, clear its content. If the file does not exist, create a file. - w+: Open a file for both reading and writing. If the file exists, clear its content. If the file does not exist, create a file. - a: Open a file in append mode for writing at the end of the file. If the file does not exist, create a file. If the file exists, write data to the end of the file (the original content of the file is reserved). - a+: Open a file in append mode for reading or updating at the end of the file. If the file does not exist, create a file. If the file exists, write data to the end of the file (the original content of the file is reserved).

Return value

Type	Description
Stream	Stream created.

Example

let filePath = pathDir + "/test.txt";
let ss = fileio.createStreamSync(filePath, "r+");

fileio.fdopenStream⁷⁺

fdopenStream(fd: number, mode: string): Promise<Stream>

Opens a stream based on the file descriptor. This API uses a promise to return the result.

NOTE

This API is deprecated since API version 9. Use fs.fdopenStream instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
fd	number	Yes	File descriptor of the target file.
mode	string	Yes	- r: Open a file for reading. The file must exist. - r+: Open a file for both reading and writing. The file must exist. - w: Open a file for writing. If the file exists, clear its content. If the file does not exist, create a file. - w+: Open a file for both reading and writing. If the file exists, clear its content. If the file does not exist, create a file. - a: Open a file in append mode for writing at the end of the file. If the file does not exist, create a file. If the file exists, write data to the end of the file (the original content of the file is reserved). - a+: Open a file in append mode for reading or updating at the end of the file. If the file does not exist, create a file. If the file exists, write data to the end of the file (the original content of the file is reserved).

Return value

Type	Description
Promise<Stream>	Promise used to return the stream opened.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
let fd = fileio.openSync(filePath);
fileio.fdopenStream(fd, "r+").then((stream: fileio.Stream) => {
  console.info("Stream opened");
}).catch((err: BusinessError) => {
  console.info("openStream failed with error:" + err);
});

fileio.fdopenStream⁷⁺

fdopenStream(fd: number, mode: string, callback: AsyncCallback<Stream>): void

Opens a stream based on the file descriptor. This API uses an asynchronous callback to return the result.

NOTE

This API is deprecated since API version 9. Use fs.fdopenStream instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
fd	number	Yes	File descriptor of the target file.
mode	string	Yes	- r: Open a file for reading. The file must exist. - r+: Open a file for both reading and writing. The file must exist. - w: Open a file for writing. If the file exists, clear its content. If the file does not exist, create a file. - w+: Open a file for both reading and writing. If the file exists, clear its content. If the file does not exist, create a file. - a: Open a file in append mode for writing at the end of the file. If the file does not exist, create a file. If the file exists, write data to the end of the file (the original content of the file is reserved). - a+: Open a file in append mode for reading or updating at the end of the file. If the file does not exist, create a file. If the file exists, write data to the end of the file (the original content of the file is reserved).
callback	AsyncCallback<Stream>	Yes	Callback invoked when the stream is open asynchronously.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
let fd = fileio.openSync(filePath);
fileio.fdopenStream(fd, "r+", (err: BusinessError, stream: fileio.Stream) => {
  // Do something.
});

fileio.fdopenStreamSync⁷⁺

fdopenStreamSync(fd: number, mode: string): Stream

Opens a stream based on the file descriptor. This API returns the result synchronously.

NOTE

This API is deprecated since API version 9. Use fs.fdopenStreamSync instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
fd	number	Yes	File descriptor of the target file.
mode	string	Yes	- r: Open a file for reading. The file must exist. - r+: Open a file for both reading and writing. The file must exist. - w: Open a file for writing. If the file exists, clear its content. If the file does not exist, create a file. - w+: Open a file for both reading and writing. If the file exists, clear its content. If the file does not exist, create a file. - a: Open a file in append mode for writing at the end of the file. If the file does not exist, create a file. If the file exists, write data to the end of the file (the original content of the file is reserved). - a+: Open a file in append mode for reading or updating at the end of the file. If the file does not exist, create a file. If the file exists, write data to the end of the file (the original content of the file is reserved).

Return value

Type	Description
Stream	Stream opened.

Example

let filePath = pathDir + "/test.txt";
let fd = fileio.openSync(filePath);
let ss = fileio.fdopenStreamSync(fd, "r+");

fileio.fchown⁷⁺

fchown(fd: number, uid: number, gid: number): Promise<void>

Changes the file owner based on the file descriptor. This API uses a promise to return the result.

NOTE

This API is deprecated since API version 9.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
fd	number	Yes	File descriptor of the target file.
uid	number	Yes	New UID.
gid	number	Yes	New GID.

Return value

Type	Description
Promise<void>	Promise that returns no value.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
let fd = fileio.openSync(filePath);
let stat = fileio.statSync(filePath);
fileio.fchown(fd, stat.uid, stat.gid).then(() => {
  console.info("File owner changed");
}).catch((err: BusinessError) => {
  console.info("chown failed with error:" + err);
});

fileio.fchown⁷⁺

fchown(fd: number, uid: number, gid: number, callback: AsyncCallback<void>): void

Changes the file owner based on the file descriptor. This API uses an asynchronous callback to return the result.

NOTE

This API is deprecated since API version 9.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
fd	number	Yes	File descriptor of the target file.
uid	number	Yes	New UID.
gid	number	Yes	New GID.
callback	AsyncCallback<void>	Yes	Callback invoked when the file owner is changed asynchronously.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
let fd = fileio.openSync(filePath);
let stat = fileio.statSync(filePath);
fileio.fchown(fd, stat.uid, stat.gid, (err: BusinessError) => {
  // Do something.
});

fileio.fchownSync⁷⁺

fchownSync(fd: number, uid: number, gid: number): void

Changes the file owner based on the file descriptor. This API returns the result synchronously.

NOTE

This API is deprecated since API version 9.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
fd	number	Yes	File descriptor of the target file.
uid	number	Yes	New UID.
gid	number	Yes	New GID.

Example

let filePath = pathDir + "/test.txt";
let fd = fileio.openSync(filePath);
let stat = fileio.statSync(filePath);
fileio.fchownSync(fd, stat.uid, stat.gid);

fileio.lchown⁷⁺

lchown(path: string, uid: number, gid: number): Promise<void>

Changes the file owner (owner of the symbolic link, not the file referred to by the symbolic link) based on the file path. This API uses a promise to return the result.

NOTE

This API is deprecated since API version 9.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the file.
uid	number	Yes	New UID.
gid	number	Yes	New GID.

Return value

Type	Description
Promise<void>	Promise that returns no value.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
let stat = fileio.statSync(filePath);
fileio.lchown(filePath, stat.uid, stat.gid).then(() => {
  console.info("File owner changed");
}).catch((err: BusinessError) => {
  console.info("chown failed with error:" + err);
});

fileio.lchown⁷⁺

lchown(path: string, uid: number, gid: number, callback: AsyncCallback<void>): void

Changes the file owner (owner of the symbolic link, not the file referred to by the symbolic link) based on the file path. This API uses an asynchronous callback to return the result.

NOTE

This API is deprecated since API version 9.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the file.
uid	number	Yes	New UID.
gid	number	Yes	New GID.
callback	AsyncCallback<void>	Yes	Callback invoked when the file owner is changed asynchronously.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
let stat = fileio.statSync(filePath);
fileio.lchown(filePath, stat.uid, stat.gid, (err: BusinessError) => {
  // Do something.
});

fileio.lchownSync⁷⁺

lchownSync(path: string, uid: number, gid: number): void

Changes the file owner based on the file path and changes the owner of the symbolic link (not the referenced file). This API returns the result synchronously.

NOTE

This API is deprecated since API version 9.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
path	string	Yes	Application sandbox path of the file.
uid	number	Yes	New UID.
gid	number	Yes	New GID.

Example

let filePath = pathDir + "/test.txt";
let stat = fileio.statSync(filePath);
fileio.lchownSync(filePath, stat.uid, stat.gid);

fileio.createWatcher⁷⁺

createWatcher(filename: string, events: number, callback: AsyncCallback<number>): Watcher

Listens for file or directory changes. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
filePath	string	Yes	Application sandbox path of the file.
events	number	Yes	- 1: The file or directory is renamed. - 2: The file or directory is modified. - 3: The file or directory is modified and renamed.
callback	AsyncCallback<number>	Yes	Called each time a change is detected.

Return value

Type	Description
Watcher	Promise used to return the Watcher instance.

Example

let filePath = pathDir +"/test.txt";
fileio.createWatcher(filePath, 1, (number: number) => {
  console.info("Monitoring times: " + number);
});

Readout

Obtains the file read result. This class applies only to the read() method.

NOTE

This API is deprecated since API version 9.

System capability: SystemCapability.FileManagement.File.FileIO

Name	Type	Readable	Writable	Description
bytesRead	number	Yes	Yes	Length of the data read.
offset	number	Yes	Yes	Position of the buffer to which the data will be read in reference to the start address of the buffer.
buffer	ArrayBuffer	Yes	Yes	Buffer for storing the data read.

Stat

Provides detailed file information. Before calling a method of the Stat class, use the stat() method synchronously or asynchronously to create a Stat instance.

NOTE

This API is deprecated since API version 9. Use fs.Stat instead.

System capability: SystemCapability.FileManagement.File.FileIO

Attributes

Name	Type	Readable	Writable	Description
dev	number	Yes	No	Major device number.
ino	number	Yes	No	File ID. Different files on the same device have different inos.
mode	number	Yes	No	File type and permissions. The first four bits indicate the file type, and the last 12 bits indicate the permissions. The bit fields are described as follows: - 0o170000: mask used to obtain the file type. - 0o140000: The file is a socket. - 0o120000: The file is a symbolic link. - 0o100000: The file is a regular file. - 0o060000: The file is a block device. - 0o040000: The file is a directory. - 0o020000: The file is a character device. - 0o010000: The file is a named pipe (FIFO). - 0o0700: mask used to obtain the owner permissions. - 0o0400: The owner has the permission to read a regular file or a directory entry. - 0o0200: The owner has the permission to write a regular file or create and delete a directory entry. - 0o0100: The owner has the permission to execute a regular file or search for the specified path in a directory. - 0o0070: mask used to obtain the user group permissions. - 0o0040: The user group has the permission to read a regular file or a directory entry. - 0o0020: The user group has the permission to write a regular file or create and delete a directory entry. - 0o0010: The user group has the permission to execute a regular file or search for the specified path in a directory. - 0o0007: mask used to obtain the permissions of other users. - 0o0004: Other users have the permission to read a regular file or a directory entry. - 0o0002: Other users have the permission to write a regular file or create and delete a directory entry. - 0o0001: Other users have the permission to execute a regular file or search for the specified path in a directory.
nlink	number	Yes	No	Number of hard links in the file.
uid	number	Yes	No	User ID, that is ID of the file owner.
gid	number	Yes	No	Group ID, that is, ID of the user group of the file.
rdev	number	Yes	No	Minor device number.
size	number	Yes	No	File size, in bytes. This parameter is valid only for regular files.
blocks	number	Yes	No	Number of blocks occupied by a file. Each block is 512 bytes.
atime	number	Yes	No	Time of the last access to the file. The value is the number of seconds elapsed since 00:00:00 on January 1, 1970.
mtime	number	Yes	No	Time of the last modification to the file. The value is the number of seconds elapsed since 00:00:00 on January 1, 1970.
ctime	number	Yes	No	Time of the last status change of the file. The value is the number of seconds elapsed since 00:00:00 on January 1, 1970.

isBlockDevice

isBlockDevice(): boolean

Checks whether this file is a block special file. A block special file supports access by block only, and it is cached when accessed.

NOTE

This API is deprecated since API version 9. Use fs.Stat.isBlockDevice instead.

System capability: SystemCapability.FileManagement.File.FileIO

Return value

Type	Description
boolean	Whether the file is a block special file.

Example

let filePath = pathDir + "/test.txt";
let isBLockDevice = fileio.statSync(filePath).isBlockDevice();

isCharacterDevice

isCharacterDevice(): boolean

Checks whether this file is a character special file. A character special file supports random access, and it is not cached when accessed.

NOTE

This API is deprecated since API version 9. Use fs.Stat.isCharacterDevice instead.

System capability: SystemCapability.FileManagement.File.FileIO

Return value

Type	Description
boolean	Whether the file is a character special file.

Example

let filePath = pathDir + "/test.txt";
let isCharacterDevice = fileio.statSync(filePath).isCharacterDevice();

isDirectory

isDirectory(): boolean

Checks whether this file is a directory.

NOTE

This API is deprecated since API version 9. Use fs.Stat.isDirectory instead.

System capability: SystemCapability.FileManagement.File.FileIO

Return value

Type	Description
boolean	Whether the file is a directory.

Example

let dirPath = pathDir + "/test";
let isDirectory = fileio.statSync(dirPath).isDirectory(); 

isFIFO

isFIFO(): boolean

Checks whether this file is a named pipe (or FIFO). Named pipes are used for inter-process communication.

NOTE

This API is deprecated since API version 9. Use fs.Stat.isFIFO instead.

System capability: SystemCapability.FileManagement.File.FileIO

Return value

Type	Description
boolean	Whether the file is an FIFO.

Example

let filePath = pathDir + "/test.txt";
let isFIFO = fileio.statSync(filePath).isFIFO(); 

isFile

isFile(): boolean

Checks whether this file is a regular file.

NOTE

This API is deprecated since API version 9. Use fs.Stat.isFile instead.

System capability: SystemCapability.FileManagement.File.FileIO

Return value

Type	Description
boolean	Whether the file is a regular file.

Example

let filePath = pathDir + "/test.txt";
let isFile = fileio.statSync(filePath).isFile();

isSocket

isSocket(): boolean

Checks whether this file is a socket.

NOTE

This API is deprecated since API version 9. Use fs.Stat.isSocket instead.

System capability: SystemCapability.FileManagement.File.FileIO

Return value

Type	Description
boolean	Whether the file is a socket.

Example

let filePath = pathDir + "/test.txt";
let isSocket = fileio.statSync(filePath).isSocket(); 

isSymbolicLink

isSymbolicLink(): boolean

Checks whether this file is a symbolic link.

NOTE

This API is deprecated since API version 9. Use fs.Stat.isSymbolicLink instead.

System capability: SystemCapability.FileManagement.File.FileIO

Return value

Type	Description
boolean	Whether the file is a symbolic link.

Example

let filePath = pathDir + "/test";
let isSymbolicLink = fileio.statSync(filePath).isSymbolicLink(); 

Watcher⁷⁺

Listens for the changes of a file. You can call the Watcher.stop() method synchronously or asynchronously to stop the listening.

stop⁷⁺

stop(): Promise<void>

Stops the watcher instance. This API uses a promise to return the result.

System capability: SystemCapability.FileManagement.File.FileIO

Example

let filePath = path + "/test.txt";
let watcher = fileio.createWatcher(filePath, 1, (number: number) => {
  console.info("Monitoring times: " + number);
});
watcher.stop().then(() => {
  console.info("Watcher stopped");
});

stop⁷⁺

stop(callback: AsyncCallback<void>): void

Stops the watcher instance. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
callback	AsyncCallback<void>	Yes	Callback invoked when watcher is stopped asynchronously.

Example

let filePath = path +"/test.txt";
let watcher = fileio.createWatcher(filePath, 1, (number: number) => {
  console.info("Monitoring times: " + number);
});
watcher.stop(() => {
  console.info("Watcher stopped");
})

Stream

Provides a stream for file operations. Before calling any API of the Stream class, use createStream() to create a Stream instance synchronously or asynchronously.

NOTE

This API is deprecated since API version 9. Use fs.Stream instead.

close⁷⁺

close(): Promise<void>

Closes the stream. This API uses a promise to return the result.

NOTE

This API is deprecated since API version 9. Use fs.Stream.close instead.

System capability: SystemCapability.FileManagement.File.FileIO

Return value

Type	Description
Promise<void>	Promise used to return the result.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
let ss = fileio.createStreamSync(filePath, "r+");
ss.close().then(() => {
  console.info("File stream closed");
}).catch((err: BusinessError) => {
  console.info("close fileStream  failed with error:" + err);
});

close⁷⁺

close(callback: AsyncCallback<void>): void

Closes the stream. This API uses an asynchronous callback to return the result.

NOTE

This API is deprecated since API version 9. Use fs.Stream.close instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
callback	AsyncCallback<void>	Yes	Callback invoked immediately after the stream is closed.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
let ss = fileio.createStreamSync(filePath, "r+");
ss.close((err: BusinessError) => {
  // Do something.
});

closeSync

closeSync(): void

Closes the stream. This API returns the result synchronously.

NOTE

This API is deprecated since API version 9. Use fs.Stream.closeSync instead.

System capability: SystemCapability.FileManagement.File.FileIO

Example

let filePath = pathDir + "/test.txt";
let ss = fileio.createStreamSync(filePath, "r+");
ss.closeSync();

flush⁷⁺

flush(): Promise<void>

Flushes the stream. This API uses a promise to return the result.

NOTE

This API is deprecated since API version 9. Use fs.Stream.flush instead.

System capability: SystemCapability.FileManagement.File.FileIO

Return value

Type	Description
Promise<void>	Promise used to return the result.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
let ss = fileio.createStreamSync(filePath, "r+");
ss.flush().then(() => {
  console.info("Stream flushed");
}).catch((err: BusinessError) => {
  console.info("flush failed with error:" + err);
});

flush⁷⁺

flush(callback: AsyncCallback<void>): void

Flushes the stream. This API uses an asynchronous callback to return the result.

NOTE

This API is deprecated since API version 9. Use fs.Stream.flush instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
callback	AsyncCallback<void>	Yes	Callback invoked when the stream is asynchronously flushed.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
let ss = fileio.createStreamSync(filePath, "r+");
ss.flush((err: BusinessError) => {
  // Do something.
});

flushSync⁷⁺

flushSync(): void

Flushes the stream. This API returns the result synchronously.

NOTE

This API is deprecated since API version 9. Use fs.Stream.flushSync instead.

System capability: SystemCapability.FileManagement.File.FileIO

Example

let filePath = pathDir + "/test.txt";
let ss = fileio.createStreamSync(filePath, "r+");
ss.flushSync();

write⁷⁺

write(buffer: ArrayBuffer|string, options?: { offset?: number; length?: number; position?: number; encoding?: string; }): Promise<number>

Writes data into the stream. This API uses a promise to return the result.

NOTE

This API is deprecated since API version 9. Use fs.Stream.write instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
buffer	ArrayBuffer|string	Yes	Data to write. It can be a string or data from a buffer.
options	Object	No	The options are as follows: - offset (number): position of the data to write in reference to the start address of the data. This parameter is optional. The default value is 0. - length (number): length of the data to write. This parameter is optional. The default value is the buffer length minus the offset. - position (number): start position to write the data in the file. This parameter is optional. By default, data is written from the current position. - encoding (string): format of the data to be encoded when the data is a string. The default value is utf-8, which is the only value supported. Constraints: offset + length <= Buffer size

Return value

Type	Description
Promise<number>	Promise used to return the length of the data written.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
let ss = fileio.createStreamSync(filePath, "r+");
class Option {
  offset: number = 0;
  length: number = 4096;
  position: number = 0;
  encoding: string = 'utf-8';
}
let option = new Option();
option.offset = 1;
option.length = 5;
option.position = 5;
ss.write("hello, world", option).then((number: number) => {
  console.info("write succeed and size is:" + number);
}).catch((err: BusinessError) => {
  console.info("write failed with error:" + err);
});

write⁷⁺

write(buffer: ArrayBuffer|string, options: { offset?: number; length?: number; position?: number; encoding?: string; }, callback: AsyncCallback<number>): void

Writes data into the stream. This API uses an asynchronous callback to return the result.

NOTE

This API is deprecated since API version 9. Use fs.Stream.write instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
buffer	ArrayBuffer|string	Yes	Data to write. It can be a string or data from a buffer.
options	Object	No	The options are as follows: - offset (number): position of the data to write in reference to the start address of the data. This parameter is optional. The default value is 0. - length (number): length of the data to write. This parameter is optional. The default value is the buffer length minus the offset. - position (number): start position to write the data in the file. This parameter is optional. By default, data is written from the current position. - encoding (string): format of the data to be encoded when the data is a string. The default value is utf-8, which is the only value supported. Constraints: offset + length <= Buffer size
callback	AsyncCallback<number>	Yes	Callback invoked when the data is written asynchronously.

Example

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
let ss = fileio.createStreamSync(filePath, "r+");
class Option {
  offset: number = 0;
  length: number = 4096;
  position: number = 0;
  encoding: string = 'utf-8';
}
let option = new Option();
option.offset = 1;
option.length = 5;
option.position = 5;
ss.write("hello, world", option, (err: BusinessError, bytesWritten: number) => {
  if (bytesWritten) {
    // Do something.
    console.info("write succeed and size is:" + bytesWritten);
  }
});

writeSync⁷⁺

writeSync(buffer: ArrayBuffer|string, options?: { offset?: number; length?: number; position?: number; encoding?: string; }): number

Writes data into the stream. This API returns the result synchronously.

NOTE

This API is deprecated since API version 9. Use fs.Stream.writeSync instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
buffer	ArrayBuffer|string	Yes	Data to write. It can be a string or data from a buffer.
options	Object	No	The options are as follows: - offset (number): position of the data to write in reference to the start address of the data. This parameter is optional. The default value is 0. - length (number): length of the data to write. This parameter is optional. The default value is the buffer length minus the offset. - position (number): start position to write the data in the file. This parameter is optional. By default, data is written from the current position. - encoding (string): format of the data to be encoded when the data is a string. The default value is utf-8, which is the only value supported. Constraints: offset + length <= Buffer size

Return value

Type	Description
number	Length of the data written in the file.

Example

let filePath = pathDir + "/test.txt";
let ss = fileio.createStreamSync(filePath,"r+");
class Option {
  offset: number = 0;
  length: number = 4096;
  position: number = 0;
  encoding: string = 'utf-8';
}
let option = new Option();
option.offset = 1;
option.length = 5;
option.position = 5;
let num = ss.writeSync("hello, world", option);

read⁷⁺

read(buffer: ArrayBuffer, options?: { position?: number; offset?: number; length?: number; }): Promise<ReadOut>

Reads data from the stream. This API uses a promise to return the result.

NOTE

This API is deprecated since API version 9. Use fs.Stream.read instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
buffer	ArrayBuffer	Yes	Buffer used to store the file read.
options	Object	No	The options are as follows: - offset (number): position to store the data read in the buffer in reference to the start address of the buffer. This parameter is optional. The default value is 0. - length (number): length of the data to read. This parameter is optional. The default value is the buffer length minus the offset. - position (number): position of the data to read in the file. This parameter is optional. By default, data is read from the current position. Constraints: offset + length <= Buffer size

Return value

Type	Description
Promise<ReadOut>	Promise used to return the data read.

Example

import { BusinessError } from '@ohos.base';
import buffer from '@ohos.buffer';
let filePath = pathDir + "/test.txt";
let ss = fileio.createStreamSync(filePath, "r+");
let arrayBuffer = new ArrayBuffer(4096);
class Option {
  offset: number = 0;
  length: number = 4096;
  position: number = 0;
}
let option = new Option();
option.offset = 1;
option.length = 5;
option.position = 5;
ss.read(arrayBuffer, option).then((readLen: number) => {
  console.info("Read data successfully");
  let buf = buffer.from(arrayBuffer, 0, readLen);
  console.info(`The content of file: ${buf.toString()}`);
}).catch((err: BusinessError) => {
  console.info("read data failed with error:" + err);
});

read⁷⁺

read(buffer: ArrayBuffer, options: { position?: number; offset?: number; length?: number; }, callback: AsyncCallback<ReadOut>): void

Reads data from the stream. This API uses an asynchronous callback to return the result.

NOTE

This API is deprecated since API version 9. Use fs.Stream.read instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
buffer	ArrayBuffer	Yes	Buffer used to store the file read.
options	Object	No	The options are as follows: - offset (number): position to store the data read in the buffer in reference to the start address of the buffer. This parameter is optional. The default value is 0. - length (number): length of the data to read. This parameter is optional. The default value is the buffer length minus the offset. - position (number): position of the data to read in the file. This parameter is optional. By default, data is read from the current position. Constraints: offset + length <= Buffer size
callback	AsyncCallback<ReadOut>	Yes	Callback invoked when data is read asynchronously from the stream.

Example

import { BusinessError } from '@ohos.base';
import buffer from '@ohos.buffer';
let filePath = pathDir + "/test.txt";
let ss = fileio.createStreamSync(filePath, "r+");
let arrayBuffer = new ArrayBuffer(4096);
class Option {
  offset: number = 0;
  length: number = 4096;
  position: number = 0;
}
let option = new Option();
option.offset = 1;
option.length = 5;
option.position = 5;
ss.read(arrayBuffer, option, (err: BusinessError, readLen: number) => {
  if (readLen) {
    console.info("Read data successfully");
    let buf = buffer.from(arrayBuffer, 0, readLen);
    console.info(`The content of file: ${buf.toString()}`);
  }
});

readSync⁷⁺

readSync(buffer: ArrayBuffer, options?: { position?: number; offset?: number; length?: number; }): number

Reads data from the stream. This API returns the result synchronously.

NOTE

This API is deprecated since API version 9. Use fs.Stream.readSync instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
buffer	ArrayBuffer	Yes	Buffer used to store the file read.
options	Object	No	The options are as follows: - offset (number): position to store the data read in the buffer in reference to the start address of the buffer. This parameter is optional. The default value is 0. - length (number): length of the data to read. This parameter is optional. The default value is the buffer length minus the offset. - position (number): position of the data to read in the file. This parameter is optional. By default, data is read from the current position. Constraints: offset + length <= Buffer size

Return value

Type	Description
number	Length of the data read.

Example

let filePath = pathDir + "/test.txt";
let ss = fileio.createStreamSync(filePath, "r+");
class Option {
  offset: number = 0;
  length: number = 4096;
  position: number = 0;
}
let option = new Option();
option.offset = 1;
option.length = 5;
option.position = 5;
let buf = new ArrayBuffer(4096)
let num = ss.readSync(buf, option);

Dir

Manages directories. Before calling a method of the Dir class, use the opendir() method synchronously or asynchronously to create a Dir instance.

NOTE

This API is deprecated since API version 9. Use fs.listFile instead.

read

read(): Promise<Dirent>

Reads the next directory entry. This API uses a promise to return the result.

NOTE

This API is deprecated since API version 9. Use fs.listFile instead.

System capability: SystemCapability.FileManagement.File.FileIO

Return value

Type	Description
Promise<Dirent>	Promise used to return the directory entry read.

Example

import { BusinessError } from '@ohos.base';
dir.read().then((dirent: fileio.Dirent) => {
  console.log("read succeed, the name of dirent is " + dirent.name);
}).catch((err: BusinessError) => {
  console.info("read failed with error:" + err);
});

read

read(callback: AsyncCallback<Dirent>): void

Reads the next directory entry. This API uses an asynchronous callback to return the result.

NOTE

This API is deprecated since API version 9. Use fs.listFile instead.

System capability: SystemCapability.FileManagement.File.FileIO

Parameters

Name	Type	Mandatory	Description
callback	AsyncCallback<Dirent>	Yes	Callback invoked when the next directory entry is asynchronously read.

Example

import { BusinessError } from '@ohos.base';
dir.read((err: BusinessError, dirent: fileio.Dirent) {
  if (dirent) {
    // Do something.
    console.log("read succeed, the name of file is " + dirent.name);
  }
});

readSync

readSync(): Dirent

Reads the next directory entry. This API returns the result synchronously.

NOTE

This API is deprecated since API version 9. Use fs.listFileSync instead.

System capability: SystemCapability.FileManagement.File.FileIO

Return value

Type	Description
Dirent	Directory entry read.

Example

let dirent = dir.readSync();

close⁷⁺

close(): Promise<void>

Closes a directory. This API uses a promise to return the result. After a directory is closed, the file descriptor in Dir will be released and no directory entry can be read from Dir.

NOTE

This API is deprecated since API version 9. Use fs.listFile instead.

System capability: SystemCapability.FileManagement.File.FileIO

Example

import { BusinessError } from '@ohos.base';
dir.close().then((err: BusinessError) => {
  console.info("close dir successfully");
});

close⁷⁺

close(callback: AsyncCallback<void>): void

Closes a directory. This API uses an asynchronous callback to return the result. After a directory is closed, the file descriptor in Dir will be released and no directory entry can be read from Dir.

NOTE

This API is deprecated since API version 9. Use fs.listFile instead.

System capability: SystemCapability.FileManagement.File.FileIO

Example

import { BusinessError } from '@ohos.base';
dir.close((err: BusinessError) => {
  console.info("close dir successfully");
});

closeSync

closeSync(): void

Closes a directory. After a directory is closed, the file descriptor in Dir will be released and no directory entry can be read from Dir.

NOTE

This API is deprecated since API version 9. Use fs.listFileSync instead.

System capability: SystemCapability.FileManagement.File.FileIO

Example

dir.closeSync();

Dirent

Provides information about files and directories. Before calling a method of the Dirent class, use the dir.read() method synchronously or asynchronously to create a Dirent instance.

NOTE

This API is deprecated since API version 9. Use fs.listFile instead.

System capability: SystemCapability.FileManagement.File.FileIO

Attributes

Name	Type	Readable	Writable	Description
name	string	Yes	No	Directory entry name.

isBlockDevice

isBlockDevice(): boolean

Checks whether this directory entry is a block special file. A block special file supports access by block only, and it is cached when accessed.

NOTE

This API is deprecated since API version 9.

System capability: SystemCapability.FileManagement.File.FileIO

Return value

Type	Description
boolean	Whether the directory entry is a block special file.

Example

let dir = fileio.opendirSync(pathDir);
let isBLockDevice = dir.readSync().isBlockDevice();

isCharacterDevice

isCharacterDevice(): boolean

Checks whether a directory entry is a character special file. A character special file supports random access, and it is not cached when accessed.

NOTE

This API is deprecated since API version 9.

System capability: SystemCapability.FileManagement.File.FileIO

Return value

Type	Description
boolean	Whether the directory entry is a character special file.

Example

let dir = fileio.opendirSync(pathDir);
let isCharacterDevice = dir.readSync().isCharacterDevice(); 

isDirectory

isDirectory(): boolean

Checks whether a directory entry is a directory.

NOTE

This API is deprecated since API version 9.

System capability: SystemCapability.FileManagement.File.FileIO

Return value

Type	Description
boolean	Whether the directory entry is a directory.

Example

let dir = fileio.opendirSync(pathDir);
let isDirectory = dir.readSync().isDirectory(); 

isFIFO

isFIFO(): boolean

Checks whether this directory entry is a named pipe (or FIFO). Named pipes are used for inter-process communication.

NOTE

This API is deprecated since API version 9.

System capability: SystemCapability.FileManagement.File.FileIO

Return value

Type	Description
boolean	Whether the directory entry is a FIFO.

Example

let dir = fileio.opendirSync(pathDir);
let isFIFO = dir.readSync().isFIFO(); 

isFile

isFile(): boolean

Checks whether a directory entry is a regular file.

NOTE

This API is deprecated since API version 9.

System capability: SystemCapability.FileManagement.File.FileIO

Return value

Type	Description
boolean	Whether the directory entry is a regular file.

Example

let dir = fileio.opendirSync(pathDir);
let isFile = dir.readSync().isFile(); 

isSocket

isSocket(): boolean

Checks whether a directory entry is a socket.

NOTE

This API is deprecated since API version 9.

System capability: SystemCapability.FileManagement.File.FileIO

Return value

Type	Description
boolean	Whether the directory entry is a socket.

Example

let dir = fileio.opendirSync(pathDir);
let isSocket = dir.readSync().isSocket(); 

isSymbolicLink

isSymbolicLink(): boolean

Checks whether a directory entry is a symbolic link.

NOTE

This API is deprecated since API version 9.

System capability: SystemCapability.FileManagement.File.FileIO

Return value

Type	Description
boolean	Whether the directory entry is a symbolic link.

Example

let dir = fileio.opendirSync(pathDir);
let isSymbolicLink = dir.readSync().isSymbolicLink();

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