# @ohos.process (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

| Name| Type| Readable| Writable| Description|
| -------- | -------- | -------- | -------- | -------- |
| egid | number | Yes| No| Effective group identifier (EGID) of the process.<br>**System API**: This is a system API.<br>It is used only to test applications.|
| euid | number | Yes| No| Effective user identifier (EUID) of the process.<br>**System API**: This is a system API.<br>It is used only to test applications.|
| gid | number | Yes| No| Group identifier (GID) of the process.<br>**System API**: This is a system API.<br>It is used only to test applications.|
| uid | number | Yes| No| User identifier (UID) of the process.|
| groups | number[] | Yes| No| Array with supplementary group IDs.<br>**System API**: This is a system API.<br>It is used only to test applications.|
| pid | number | Yes| No| Process ID (PID) of the process.|
| ppid | number | Yes| No| Parent process ID (PPID) of the process.<br>**System API**: This is a system API.<br>It is used only to test applications.|
| tid<sup>8+</sup> | number | Yes| No| Thread ID (TID) of the thread.|


## EventListener

**System capability**: SystemCapability.Utils.Lang

| Name| Description|
| -------- | -------- |
| EventListener&nbsp;=&nbsp;(evt: &nbsp;Object)&nbsp;=&gt;&nbsp;void | Event to store.|


## process.isIsolatedProcess<sup>8+</sup>

isIsolatedProcess(): boolean

Checks whether this process is isolated.

**System capability**: SystemCapability.Utils.Lang

**Return value**

| Type| Description|
| -------- | -------- |
| boolean | Returns **true** if the process is isolated; returns **false** otherwise.|

**Example**

```js
let result = process.isIsolatedProcess();
```


## process.is64Bit<sup>8+</sup>

is64Bit(): boolean

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

**System capability**: SystemCapability.Utils.Lang

**Return value**

| Type| Description|
| -------- | -------- |
| boolean | Returns **true** if the process is running in a 64-bit environment; returns **false** otherwise.|

**Example**

```js
let result = process.is64Bit();
```


## process.getStartRealtime<sup>8+</sup>

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**

| Type| Description|
| -------- | -------- |
| number | Duration obtained, in millisecond.|

**Example**

```js
let realtime = process.getStartRealtime();
```

## process.getPastCpuTime<sup>8+</sup>

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**

| Type| Description|
| -------- | -------- |
| number | CPU time obtained, in millisecond.|

**Example**

```js
let result = process.getPastCpuTime() ;
```


## 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.

**System API**: This is a system API.

It is used only to test applications.

**System capability**: SystemCapability.Utils.Lang

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| command | string | Yes| Shell command to run.|
| options | Object | No| Related parameters.|

**Table 1** options

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| timeout | number | No| Maximum running time (in milliseconds) of the child process. When the running time of the child process exceeds the value of this parameter, the parent process sends a **killSignal** to the child process to terminate it. The default value is **0**.|
| killSignal | number&nbsp;\|&nbsp;string | No| Signal sent to the child process when the running time of a child process exceeds the timeout period. The default value is **SIGTERM**.|
| maxBuffer | number | No| Maximum buffer size for the standard input and output of the child process. When the size is exceeded, the child process will be terminated. The default value is **1024 \* 1024**.|

**Return value**

| Type| Description|
| -------- | -------- |
| [ChildProcess](#childprocess) | **ChildProcess** object.|

**Example**

```js
let child = process.runCmd('ls', { maxBuffer : 2 });
let 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**

```js
process.abort();
```


## process.on

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

Stores the events triggered by the user.

**System API**: This is a system API.

It is used only to test applications.

**System capability**: SystemCapability.Utils.Lang

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| type | string | Yes| Type of the events to store. |
| listener | [EventListener](#eventlistener) | Yes| Callback invoked to return the event.|

**Example**

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


## process.off

off(type: string): boolean

Deletes the event stored by the user.

**System API**: This is a system API.

It is used only to test applications.

**System capability**: SystemCapability.Utils.Lang

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| type | string | Yes| Type of the event to delete.|

**Return value**

| Type| Description|
| -------- | -------- |
| boolean | Returns **true** if the event is deleted; returns **false** otherwise.|

**Example**

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


## process.cwd

cwd(): string

Obtains the working directory of this process.

**System API**: This is a system API.

It is used only to test applications.

**System capability**: SystemCapability.Utils.Lang

**Return value**

| Type| Description|
| -------- | -------- |
| string| Working directory obtained.|

**Example**

```js
let path = process.cwd();
```


## process.chdir

chdir(dir: string): void

Changes the working directory of this process.

**System API**: This is a system API.

It is used only to test applications.

**System capability**: SystemCapability.Utils.Lang

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| dir | string | Yes| Path|

**Example**

```js
process.chdir('/system');
```


## process.uptime

uptime(): number

Obtains the running time of this process.

**System capability**: SystemCapability.Utils.Lang

**Return value**

| Type| Description|
| -------- | -------- |
| number | Running time of the process, in seconds.|

**Example**

```js
let time = process.uptime();
```


## process.kill<sup>(deprecated)</sup>

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

Sends a signal to the specified process to terminate it.

> **NOTE**
>
> This API is supported since API version 7 and deprecated since API version 9. You are advised to use [kill<sup>9+</sup>](#kill9) instead.

**System capability**: SystemCapability.Utils.Lang

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| pid | number | Yes| PID of the process, to which the signal will be sent.|
| signal | number | Yes| Signal to send.|

**Return value**

| Type| Description|
| -------- | -------- |
| boolean | Returns **true** if the signal is sent successfully; returns **false** otherwise.|

**Example**

```js
let pres = process.pid
let result = process.kill(28, pres)
```


## process.exit<sup>(deprecated)</sup>

exit(code: number): void

Terminates this process.

Exercise caution when using this API. After this API is called, the application exits. If the input parameter is not 0, data loss or exceptions may occur.

> **NOTE**
>
> This API is supported since API version 7 and deprecated since API version 9. You are advised to use [exit<sup>9+</sup>](#exit9) instead.

**System capability**: SystemCapability.Utils.Lang

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| code | number | Yes| Exit code of the process.|

**Example**

```js
process.exit(0);
```


## process.getUidForName<sup>(deprecated)</sup>

getUidForName(v: string): number

Obtains the process UID based on the process name.

> **NOTE**
>
> This API is supported since API version 8 and deprecated since API version 9. You are advised to use [getUidForName<sup>9+</sup>](#getuidforname9) instead.

**System capability**: SystemCapability.Utils.Lang

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| v | string | Yes| Name of a process.|

**Return value**

| Type| Description|
| -------- | -------- |
| number | Process UID.|

**Example**

```js
let pres = process.getUidForName("tool")
```


## process.getThreadPriority<sup>(deprecated)</sup>

getThreadPriority(v: number): number

Obtains the thread priority based on the specified TID.

> **NOTE**
>
> This API is supported since API version 8 and deprecated since API version 9. You are advised to use [getThreadPriority<sup>9+</sup>](#getthreadpriority9) instead.

**System capability**: SystemCapability.Utils.Lang

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| v | number | Yes| TID.|

**Return value**

| Type| Description|
| -------- | -------- |
| number | Priority of the thread.|

**Example**

```js
let tid = process.tid;
let pres = process.getThreadPriority(tid);
```


## process.isAppUid<sup>(deprecated)</sup>

isAppUid(v: number): boolean

Checks whether a UID belongs to this application.

> **NOTE**
>
> This API is supported since API version 8 and deprecated since API version 9. You are advised to use [isAppUid<sup>9+</sup>](#isappuid9) instead.

**System capability**: SystemCapability.Utils.Lang

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| v | number | Yes| UID.|

**Return value**

| Type| Description|
| -------- | -------- |
| boolean | Returns **true** if the UID belongs to the application; returns **false** otherwise.|

**Example**

```js
let result = process.isAppUid(688);
```


## process.getSystemConfig<sup>(deprecated)</sup>

getSystemConfig(name: number): number

Obtains the system configuration.

> **NOTE**
>
> This API is supported since API version 8 and deprecated since API version 9. You are advised to use [getSystemConfig<sup>9+</sup>](#getsystemconfig9) instead.

**System capability**: SystemCapability.Utils.Lang

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| name | number | Yes| System configuration parameter name.|

**Return value**

| Type| Description|
| -------- | -------- |
| number | System configuration obtained.|

**Example**

```js
let _SC_ARG_MAX = 0
let pres = process.getSystemConfig(_SC_ARG_MAX)
```


## process.getEnvironmentVar<sup>(deprecated)</sup>

getEnvironmentVar(name: string): string

Obtains the value of an environment variable.

> **NOTE**
>
> This API is supported since API version 8 and deprecated since API version 9. You are advised to use [getEnvironmentVar<sup>9+</sup>](#getenvironmentvar9) instead.

**System capability**: SystemCapability.Utils.Lang

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| name | string | Yes| Environment variable name.|

**Return value**

| Type| Description|
| -------- | -------- |
| string | Value of the environment variable.|

**Example**

```js
let pres = process.getEnvironmentVar("PATH")
```


## ProcessManager<sup>9+</sup>	

Provides APIs for throwing exceptions during the addition of a process.

A **ProcessManager** object is obtained through its own constructor.

### isAppUid<sup>9+</sup>

isAppUid(v: number): boolean

Checks whether a UID belongs to this application.

**System capability**: SystemCapability.Utils.Lang

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| v | number | Yes| UID.|

**Return value**

| Type| Description|
| -------- | -------- |
| boolean | Returns **true** if the UID belongs to the application; returns **false** otherwise.|

**Example**

```js
let pro = new process.ProcessManager();
let result = pro.isAppUid(688);
```


### getUidForName<sup>9+</sup>

getUidForName(v: string): number

Obtains the process UID based on the process name.

**System capability**: SystemCapability.Utils.Lang

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| v | string | Yes| Name of a process.|

**Return value**

| Type| Description|
| -------- | -------- |
| number | Process UID.|

**Example**

```js
let pro = new process.ProcessManager();
let pres = pro .getUidForName("tool");
```


### getThreadPriority<sup>9+</sup>

getThreadPriority(v: number): number

Obtains the thread priority based on the specified TID.

**System capability**: SystemCapability.Utils.Lang

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| v | number | Yes| TID.|

**Return value**

| Type| Description|
| -------- | -------- |
| number | Priority of the thread.|

**Example**

```js
let pro = new process.ProcessManager();
let tid = process.tid;
let pres = pro.getThreadPriority(tid);
```


### getSystemConfig<sup>9+</sup>

getSystemConfig(name: number): number

Obtains the system configuration.

**System capability**: SystemCapability.Utils.Lang

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| name | number | Yes| System configuration parameter name.|

**Return value**

| Type| Description|
| -------- | -------- |
| number | System configuration obtained.|

**Example**

```js
let pro = new process.ProcessManager();
let _SC_ARG_MAX = 0;
let pres = pro.getSystemConfig(_SC_ARG_MAX);
```


### getEnvironmentVar<sup>9+</sup>

getEnvironmentVar(name: string): string

Obtains the value of an environment variable.

**System capability**: SystemCapability.Utils.Lang

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| name | string | Yes| Environment variable name.|

**Return value**

| Type| Description|
| -------- | -------- |
| string | Value of the environment variable.|

**Example**

```js
let pro = new process.ProcessManager();
let pres = pro.getEnvironmentVar("PATH");
```


### exit<sup>9+</sup>

exit(code: number): void

Terminates this process.

Exercise caution when using this API. After this API is called, the application exits. If the input parameter is not 0, data loss or exceptions may occur.

**System capability**: SystemCapability.Utils.Lang

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| code | number | Yes| Exit code of the process.|

**Example**

```js
let pro = new process.ProcessManager();
pro.exit(0);
```


### kill<sup>9+</sup>

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

Sends a signal to the specified process to terminate it.

**System capability**: SystemCapability.Utils.Lang

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| pid | number | Yes| PID of the process, to which the signal will be sent.|
| signal | number | Yes| Signal to send.|

**Return value**

| Type| Description|
| -------- | -------- |
| boolean | Returns **true** if the signal is sent successfully; returns **false** otherwise.|

**Example**

```js
let pro = new process.ProcessManager();
let pres = process.pid;
let result = pro.kill(28, pres);
```


## ChildProcess

The **ChildProcess** object is a new child process and can be obtained by calling [process.runCmd](#processruncmd). The main process can obtain the standard input and output of the child process, send signals to the child process, and close the child process.

**System API**: This is a system API.

### Attributes

**System API**: This is a system API.

**System capability**: SystemCapability.Utils.Lang

| Name| Type| Readable| Writable| Description|
| -------- | -------- | -------- | -------- | -------- |
| pid | number | Yes| No| PID of the child process.<br>**System API**: This is a system API.<br>It is used only to test applications.|
| ppid | number | Yes| No| PPID of the child process.<br>**System API**: This is a system API.<br>It is used only to test applications.|
| exitCode | number | Yes| No| Exit code of the child process.<br>**System API**: This is a system API.<br>It is used only to test applications.|
| killed | boolean | Yes| No| Whether the parent process successfully sends a signal to the child process to terminate it.<br>**System API**: This is a system API.<br>It is used only to test applications.|


### wait

wait(): Promise&lt;number&gt;

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

**System API**: This is a system API.

It is used only to test applications.

**System capability**: SystemCapability.Utils.Lang

**Return value**

| Type| Description|
| -------- | -------- |
| Promise&lt;number&gt; | Promise used to return the exit code of the child process.|

**Example**

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


### getOutput

getOutput(): Promise&lt;Uint8Array&gt;

Obtains the standard output of the child process.

**System API**: This is a system API.

It is used only to test applications.

**System capability**: SystemCapability.Utils.Lang

**Return value**

| Type| Description|
| -------- | -------- |
| Promise&lt;Uint8Array&gt; | Promise used to return the standard output in a Uint8Array.|

**Example**

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


### getErrorOutput

getErrorOutput(): Promise&lt;Uint8Array&gt;

Obtains the standard error output of the child process.

**System API**: This is a system API.

It is used only to test applications.

**System capability**: SystemCapability.Utils.Lang

**Return value**

| Type| Description|
| -------- | -------- |
| Promise&lt;Uint8Array&gt; | Promise used to return the standard error output in a Uint8Array.|

**Example**

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


### close

close(): void

Closes the child process in running.

**System API**: This is a system API.

It is used only to test applications.

**System capability**: SystemCapability.Utils.Lang

**Example**

```js
let 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.

**System API**: This is a system API.

It is used only to test applications.

**System capability**: SystemCapability.Utils.Lang

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| signal | number&nbsp;\|&nbsp;string | Yes| Number or string to send.|

**Example**

```js
let child = process.runCmd('sleep 5; ls');
child.kill(9);
```