Obtaining Process Information

NOTE The initial APIs of this module are supported since API version 7. Newly added APIs will be marked with a superscript to indicate their earliest API version.

Modules to Import

import process from '@ohos.process';

Attributes

System capability: SystemCapability.Utils.Lang

ChildProcess

Allows a process to obtain the standard input and output of its child processes, send signals, and close its child processes.

Attributes

System capability: SystemCapability.Utils.Lang

wait

wait(): Promise<number>

Waits until the child process ends. This method uses a promise to return the exit code of the child process.

This is a system API and cannot be called by third-party applications.

System capability: SystemCapability.Utils.Lang

Return value

Example

var child = process.runCmd('ls');
var result = child.wait();
result.then(val=>{
    console.log("result = " + val);
})

getOutput

getOutput(): Promise<Uint8Array>

Obtains the standard output of the child process.

This is a system API and cannot be called by third-party applications.

System capability: SystemCapability.Utils.Lang

Return value

Example

var child = process.runCmd('ls');
var result = child.wait();
child.getOutput.then(val=>{
    console.log("child.getOutput = " + val);
})

getErrorOutput

getErrorOutput(): Promise<Uint8Array>

Obtains the standard error output of the child process.

This is a system API and cannot be called by third-party applications.

System capability: SystemCapability.Utils.Lang

Return value

Example

var child = process.runCmd('madir test.text');
var result = child.wait();
child.getErrorOutput.then(val=>{
    console.log("child.getErrorOutput= " + val);
})

close

close(): void

Closes the child process in running.

This is a system API and cannot be called by third-party applications.

System capability: SystemCapability.Utils.Lang

Example

var child = process.runCmd('sleep 5; ls');
child.close();

kill

kill(signal: number | string): void

Sends a signal to the specified child process to terminate it.

This is a system API and cannot be called by third-party applications.

System capability: SystemCapability.Utils.Lang

Parameters

Example

var child = process.runCmd('sleep 5; ls');
child.kill(9);

process.isIsolatedProcess⁸⁺

isIsolatedProcess(): boolean

Checks whether this process is isolated.

System capability: SystemCapability.Utils.Lang

Return value

Example

var result = process.isIsolatedProcess();

process.isAppUid⁸⁺

isAppUid(v: number): boolean

Checks whether a UID belongs to this app.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

Example

var result = process.isAppUid(688);

process.is64Bit⁸⁺

is64Bit(): boolean

Checks whether this process is running in a 64-bit environment.

System capability: SystemCapability.Utils.Lang

Return value

Example

var ressult = process.is64Bit();

process.getUidForName⁸⁺

getUidForName(v: string): number

Obtains the process UID based on the process name.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

Example

var pres = process.getUidForName("tool")

process.getThreadPriority⁸⁺

getThreadPriority(v: number): number

Obtains the thread priority based on the specified TID.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

Example

var tid = process.getTid();
var pres = process.getThreadPriority(tid);

process.getStartRealtime⁸⁺

getStartRealtime(): number

Obtains the duration, in milliseconds, from the time the system starts to the time the process starts.

System capability: SystemCapability.Utils.Lang

Return value

Example

var realtime = process.getStartRealtime();

process.getPastCpuTime⁸⁺

getPastCpuTime(): number

Obtains the CPU time (in milliseconds) from the time the process starts to the current time.

System capability: SystemCapability.Utils.Lang

Return value

Example

var result = process.getPastCpuTime() ;

process.getSystemConfig⁸⁺

getSystemConfig(name: number): number

Obtains the system configuration.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

Example

var _SC_ARG_MAX = 0
var pres = process.getSystemConfig(_SC_ARG_MAX)

process.getEnvironmentVar⁸⁺

getEnvironmentVar(name: string): string

Obtains the value of an environment variable.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

Example

var pres = process.getEnvironmentVar("PATH")

process.runCmd

runCmd(command: string, options?: { timeout : number, killSignal : number | string, maxBuffer : number }): ChildProcess

Forks a new process to run a shell command and returns the ChildProcess object.

This is a system API and cannot be called by third-party applications.

System capability: SystemCapability.Utils.Lang

Parameters

Table 1 options

Return value

Example

var child = process.runCmd('ls', { maxBuffer : 2 });
var result = child.wait();
child.getOutput.then(val=>{
    console.log("child.getOutput = " + val);
})

process.abort

abort(): void

Aborts a process and generates a core file. This method will cause a process to exit immediately. Exercise caution when using this method.

System capability: SystemCapability.Utils.Lang

Example

process.abort();

process.on

on(type: string, listener: EventListener): void

Stores the events triggered by the user.

This is a system API and cannot be called by third-party applications.

System capability: SystemCapability.Utils.Lang

Parameters

Table 2 EventListener

Example

process.on("data", (e)=>{
    console.log("data callback");
})

process.off

off(type: string): boolean

Deletes the event stored by the user.

This is a system API and cannot be called by third-party applications.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

Example

process.on("data", (e)=>{
    console.log("data callback");
})
var result = process.off("data");

process.exit

exit(code: number): void

Terminates this process.

Exercise caution when using this API.

System capability: SystemCapability.Utils.Lang

Parameters

Example

process.exit(0);

process.cwd

cwd(): string

Obtains the working directory of this process.

This is a system API and cannot be called by third-party applications.

System capability: SystemCapability.Utils.Lang

Example

var path = process.cwd();

process.chdir

chdir(dir: string): void

Changes the working directory of this process.

This is a system API and cannot be called by third-party applications.

System capability: SystemCapability.Utils.Lang

Parameters

Example

process.chdir('/system');

process.uptime

uptime(): number

Obtains the running time of this process.

System capability: SystemCapability.Utils.Lang

Return value

Example

var time = process.uptime();

process.kill

kill(signal: number, pid: number): boolean

Sends a signal to the specified process to terminate it.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

Example

var pres = process.pid
var result = that.kill(28, pres)