The background_process_manager.h file declares the APIs for background child process management. You can use these APIs to suppress and unsuppress child processes to prevent child processes from occupying too many system resources and causing system stuttering. The APIs take effect only for the child processes created through OH_Ability_StartNativeChildProcess.
File to include: <background_process_manager/background_process_manager.h>
Library: libbackground_process_manager.z.so
System capability: SystemCapability.Resourceschedule.BackgroundProcessManager
Since: 17
Related module: BackgroundProcessManager
| Name | typedef Keyword | Description |
|---|---|---|
| BackgroundProcessManager_ProcessPriority | BackgroundProcessManager_ProcessPriority | Enumerates child process priorities. |
| BackgroundProcessManager_ErrorCode | BackgroundProcessManager_ErrorCode | Enumerates the error codes used by the background child process management. |
| Name | Description |
|---|---|
| int OH_BackgroundProcessManager_SetProcessPriority(int pid, BackgroundProcessManager_ProcessPriority priority) | Sets the child process priority. After a child process is suppressed, the CPU resources that can be obtained will be limited. If the scheduling policy of the main process changes, for example, from the background to the foreground, the child process changes with the main process. To suppress the child process, call this API again. |
| int OH_BackgroundProcessManager_ResetProcessPriority(int pid) | Unsuppresses the child process. In this case, the child process follows the scheduling policy of the main process. If the scheduling policy of the main process changes, for example, from the background to the foreground, the child process changes with the main process. The effect is the same as calling resetProcessPriority. |
enum BackgroundProcessManager_ProcessPriority
Description
Enumerates child process priorities.
Since: 17
| Enum | Description |
|---|---|
| PROCESS_BACKGROUND = 1 | Compared with PROCESS_INACTIVE, this priority has a more obvious suppression effect. Child processes can obtain less CPU resources. You are advised to set this priority when executing background child processes that cannot be perceived by users, such as background image-text pages. |
| PROCESS_INACTIVE = 2 | You are advised to set this priority when executing background child processes that can be perceived by users, such as audio playback and navigation. |
enum BackgroundProcessManager_ErrorCode
Description
Enumerates the error codes used by the background child process management.
Since: 17
| Enum | Description |
|---|---|
| ERR_BACKGROUND_PROCESS_MANAGER_SUCCESS = 0 | The suppression parameter is sent successfully. |
| ERR_BACKGROUND_PROCESS_MANAGER_INVALID_PARAM = 401 | Parameter check fails. |
| ERR_BACKGROUND_PROCESS_MANAGER_REMOTE_ERROR = 31800001 | The client process fails to obtain the system service. |
int OH_BackgroundProcessManager_SetProcessPriority(int pid, BackgroundProcessManager_ProcessPriority priority)
Description
Sets the child process priority. After a child process is suppressed, the CPU resources that can be obtained will be limited. If the scheduling policy of the main process changes, for example, from the background to the foreground, the child process changes with the main process. To suppress the child process, call this API again.
Since: 17
Parameters
| Name | Description |
|---|---|
| int pid | ID of the child process to be suppressed, which is the value of the pid parameter after the child process is created through the OH_Ability_StartNativeChildProcess API. |
| BackgroundProcessManager_ProcessPriority priority | Suppression priority. |
Returns
| Type | Description |
|---|---|
| int | ERR_BACKGROUND_PROCESS_MANAGER_SUCCESS is returned if the suppression parameter is sent successfully. ERR_BACKGROUND_PROCESS_MANAGER_INVALID_PARAM is returned if the parameter check fails. |
int OH_BackgroundProcessManager_ResetProcessPriority(int pid)
Description
Unsuppresses the child process. In this case, the child process follows the scheduling policy of the main process. If the scheduling policy of the main process changes, for example, from the background to the foreground, the child process changes with the main process. The effect is the same as calling resetProcessPriority.
Since: 17
Parameters
| Name | Description |
|---|---|
| int pid | ID of the child process, which is the value of the pid parameter of the OH_Ability_StartNativeChildProcess API. |
Returns
| Type | Description |
|---|---|
| int | ERR_BACKGROUND_PROCESS_MANAGER_SUCCESS is returned if the decompression is successful. |