harmony 鸿蒙Accessing Application Files (C/C++)

2025-06-12
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Accessing Application Files (C/C++)

When to Use

The FileIO module provides some APIs for basic file operations. For details about other APIs, see libc and libc++.

Basic Concepts

URI: uniquely identifies a file.

Constraints

Before performing file operations, ensure that the URI or path passed in is correct and valid.

Available APIs

For details about the APIs, see FileIO.

API	Description
FileManagement_ErrCode OH_FileIO_GetFileLocation(char uri, int uriLength, FileIO_FileLocation location)	Obtains the location of a file.
enum FileIO_FileLocation FileIO_FileLocation	Enumerates the file locations.
enum FileManagement_ErrCode FileManagement_ErrCode	Enumerates the error codes used in the FileIO module.

How to Develop

Adding the Dynamic Link Library

Add the following library to CMakeLists.txt.

target_link_libraries(sample PUBLIC libohfileio.so)

Adding the Header File

#include <cstdio>
#include <cstring>
#include <filemanagement/fileio/oh_fileio.h>

Call OH_FileIO_GetFileLocation to obtain the location of a file.
Example:

    void GetFileLocationExample() {
        char *uri = "file://com.example.demo/data/storage/el2/base/files/test.txt";
        FileIO_FileLocation location;
        FileManagement_ErrCode ret = OH_FileIO_GetFileLocation(uri, strlen(uri), &location);
        if (ret == 0) {
            if (location == FileIO_FileLocation::LOCAL) {
                printf("This file is on local.");
            } else if (location == FileIO_FileLocation::CLOUD) {
                printf("This file is on cloud.");
            } else if (location == FileIO_FileLocation::LOCAL_AND_CLOUD) {
                printf("This file is both on local and cloud.");
            }
        } else {
            printf("GetFileLocation failed, error code is %d", ret);
        }
    }