1# native_child_process.h
2
3
4## Overview
5
6The **native_child_process.h** file declares the APIs used to create a native child process and establish an IPC channel between the main process and child process. A maximum of 512 child processes can be started through this module and [childProcessManager](js-apis-app-ability-childProcessManager.md) (non-SELF_FORK mode).
7
8**Library**: libchild_process.so
9
10**System capability**: SystemCapability.Ability.AbilityRuntime.Core
11
12**Since**: 12
13
14**Related module**: [ChildProcess](c-apis-ability-childprocess.md)
15
16
17## Summary
18
19### Files
20
21| Name                                                    | Description                                                                                                |
22| ------------------------------------------------------ | -------------------------------------------------------------------------------------------------- |
23| [native_child_process.h](native__child__process_8h.md) | Declares the APIs used to create a native child process and establish an IPC channel between the main process and child process.<br>File to include: <AbilityKit/native_child_process.h><br>Library: libchild_process.so|
24
25### Types
26
27| Name                                                                                                                                                                            | Description               |
28| ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ----------------- |
29| typedef enum Ability_NativeChildProcess_ErrCode [Ability_NativeChildProcess_ErrCode](c-apis-ability-childprocess.md#ability_nativechildprocess_errcode)                        | Defines an enum for the error codes used by the native child process module.|
30| typedef void(\* [OH_Ability_OnNativeChildProcessStarted](c-apis-ability-childprocess.md#oh_ability_onnativechildprocessstarted)) (int errCode, OHIPCRemoteProxy \*remoteProxy) | Defines a callback function for notifying the child process startup result.|
31| typedef struct [NativeChildProcess_Fd](c-apis-ability-childprocess.md#nativechildprocess_fd) | Defines a struct for the file descriptor of a child process.|
32| typedef struct [NativeChildProcess_FdList](c-apis-ability-childprocess.md#nativechildprocess_fdlist) | Defines a struct for the linked list of file descriptors of a child process.|
33| typedef struct [NativeChildProcess_Args](c-apis-ability-childprocess.md#nativechildprocess_args) | Defines a struct for the arguments used for starting a child process.|
34| typedef struct [NativeChildProcess_Options](c-apis-ability-childprocess.md#nativechildprocess_options) | Defines a struct for the startup configuration options of a child process.|
35
36
37### Enums
38
39| Name                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | Description               |
40| -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------- |
41| [Ability_NativeChildProcess_ErrCode](c-apis-ability-childprocess.md#ability_nativechildprocess_errcode) {<br>    NCP_NO_ERROR = 0,<br>    NCP_ERR_INVALID_PARAM = 401,<br>    NCP_ERR_NOT_SUPPORTED = 801,<br>    NCP_ERR_INTERNAL = 16000050,<br>    NCP_ERR_BUSY = 16010001,<br>    NCP_ERR_TIMEOUT = 16010002,<br>    NCP_ERR_SERVICE_ERROR = 16010003,<br>    NCP_ERR_MULTI_PROCESS_DISABLED = 16010004,<br>    NCP_ERR_ALREADY_IN_CHILD = 16010005,<br>    NCP_ERR_MAX_CHILD_PROCESSES_REACHED = 16010006,<br>    NCP_ERR_LIB_LOADING_FAILED = 16010007,<br>    NCP_ERR_CONNECTION_FAILED = 16010008<br>} | Enumerates the error codes used by the native child process module.|
42| [NativeChildProcess_IsolationMode](c-apis-ability-childprocess.md#nativechildprocess_isolationmode) {<br>    NCP_ISOLATION_MODE_NORMAL = 0,<br>    NCP_ISOLATION_MODE_ISOLATED = 1,<br>} | Enumerates the isolation modes of a child process.|
43
44
45### Functions
46
47| Name                                                         | Description                                                  |
48| ------------------------------------------------------------ | ------------------------------------------------------------ |
49| int [OH_Ability_CreateNativeChildProcess](c-apis-ability-childprocess.md#oh_ability_createnativechildprocess) (const char \*libName, [OH_Ability_OnNativeChildProcessStarted](c-apis-ability-childprocess.md#oh_ability_onnativechildprocessstarted) onProcessStarted) | Creates a child process, loads the specified dynamic library file, and returns the startup result asynchronously through a callback parameter. The callback notification is an independent thread. When implementing the callback function, pay attention to thread synchronization and do not perform time-consuming operations to avoid long-time blocking.<br><b>NOTE</b><br/>Currently, this function is valid only for 2-in-1 devices, and a process can start only one native child process by using this function. |
50| [Ability_NativeChildProcess_ErrCode](c-apis-ability-childprocess.md#ability_nativechildprocess_errcode) [OH_Ability_StartNativeChildProcess](c-apis-ability-childprocess.md#oh_ability_startnativechildprocess)(const char\* entry, [NativeChildProcess_Args](c-apis-ability-childprocess.md#nativechildprocess_args) args, [NativeChildProcess_Options](c-apis-ability-childprocess.md#nativechildprocess_options) options, int32_t *pid) | Starts a child process, loads the specified dynamic library file, and calls the entry function. Arguments can be passed to the child process.<br><b>NOTE</b><br/>Currently, this function is valid only for 2-in-1 devices and tablets. |
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