harmony 鸿蒙@ohos.app.ability.childProcessManager (childProcessManager)

2023-10-30
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@ohos.app.ability.childProcessManager (childProcessManager)

The childProcessManager module provides the child process management capability. Currently, it provides APIs to start the child process.

NOTE

The initial APIs of this module are supported since API version 11. Newly added APIs will be marked with a superscript to indicate their earliest API version.

The APIs of this module can be used only in the stage model.

Modules to Import

import childProcessManager from '@ohos.app.ability.childProcessManager';

childProcessManager.StartMode

Enumerates the child process start modes.

System capability: SystemCapability.Ability.AbilityRuntime.Core

Name	Value	Description
SELF_FORK	0	The child process is forked from the application process. Binder IPC cannot be called in such a child process. Otherwise, the child process will crash.

childProcessManager.startChildProcess

startChildProcess(srcEntry: string, startMode: StartMode): Promise<number>;

Creates a child process and invokes the entrypoint method of the child process. This API uses a promise to return the result. A PID is returned once the child process is created. However, this does not mean that the child process is started. It is started only when the entrypoint method of the child process is successfully invoked.

System capability: SystemCapability.Ability.AbilityRuntime.Core

Parameters

Name	Type	Mandatory	Description
srcEntry	string	Yes	Relative path of the source file of the child process.
startMode	StartMode	Yes	Start mode of the child process.

Return value

Type	Description
Promise<number>	Promise used to return the PID of the child process.

Error codes

For details about the error codes, see Ability Error Codes.

ID	Error Message
16000050	Internal error.
16000061	Operation not supported.
16000062	The number of child process exceeds upper bound.

Example

// Create the child process class DemoProcess.ts in src/main/ets/process of the entry module.
import ChildProcess from '@ohos.app.ability.ChildProcess';

export default class DemoProcess extends ChildProcess {
  onStart() {
    console.log("DemoProcess OnStart() called");
  }
}

// Call childProcessManager.startChildProcess to start the child process.
import childProcessManager from '@ohos.app.ability.childProcessManager';

try {
  childProcessManager.startChildProcess("./ets/process/DemoProcess.ts", childProcessManager.StartMode.SELF_FORK)
    .then((data) => {
      console.log(`startChildProcess success, pid: ${data}`);
    }, (err: BusinessError) => {
      console.error(`startChildProcess error, errorCode: ${err.code}`);
    })
} catch (err) {
  console.error(`startChildProcess error, errorCode: ${err.code}`);
}

childProcessManager.startChildProcess

startChildProcess(srcEntry: string, startMode: StartMode, callback: AsyncCallback<number>): void;

Creates a child process and invokes the entrypoint method of the child process. This API uses an asynchronous callback to return the result. A PID is returned once the child process is created. However, this does not mean that the child process is started. It is started only when the entrypoint method of the child process is successfully invoked.

System capability: SystemCapability.Ability.AbilityRuntime.Core

Parameters

Name	Type	Mandatory	Description
srcEntry	string	Yes	Relative path of the source file of the child process.
startMode	StartMode	Yes	Start mode of the child process.
callback	AsyncCallback<number>	Yes	Callback used to return the PID of the child process.

Error codes

For details about the error codes, see Ability Error Codes.

ID	Error Message
16000050	Internal error.
16000061	Operation not supported.
16000062	The number of child process exceeds upper bound.

Example

// Create the child process class DemoProcess.ts in src/main/ets/process of the entry module.
import ChildProcess from '@ohos.app.ability.ChildProcess';

export default class DemoProcess extends ChildProcess {
  onStart() {
    console.log("DemoProcess OnStart() called");
  }
}

// Call childProcessManager.startChildProcess to start the child process.
import childProcessManager from '@ohos.app.ability.childProcessManager';

try {
  childProcessManager.startChildProcess("./ets/process/DemoProcess.ts", childProcessManager.StartMode.SELF_FORK, (err, data) => {
    if (data) {
      console.log(`startChildProcess success, pid: ${data}`);
    } else {
      console.error(`startChildProcess error, errorCode: ${err.code}`);
    }
  });
} catch (err) {
  console.error(`startChildProcess error, errorCode: ${err.code}`);
}