@ohos.app.ability.childProcessManager (childProcessManager)

The childProcessManager module provides the child process management capability. Currently, it provides APIs to start the child process and is available only for tablets.

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

childProcessManager.startChildProcess

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

Creates a child process and invokes the entrypoint method of the child process. 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. This API cannot be called by a child process to create its child process. This API uses a promise to return the result.

System capability: SystemCapability.Ability.AbilityRuntime.Core

Parameters

Return value

Error codes

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

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';
import DemoProcess from '../process/DemoProcess';
import { BusinessError } from '@ohos.base';

try {
  DemoProcess.toString(); // Call any API of the DemoProcess class to prevent the code from being directly optimized by the compiler because it is not being referenced.
  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 as BusinessError).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. 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. This API cannot be called by a child process to create its child process. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.Ability.AbilityRuntime.Core

Parameters

Error codes

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

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';
import DemoProcess from '../process/DemoProcess';
import { BusinessError } from '@ohos.base';

try {
  DemoProcess.toString(); // Call any API of the DemoProcess class to prevent the code from being directly optimized by the compiler because it is not being referenced.
  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 as BusinessError).code}`);
}