# appspawn Module for the Standard System<a name="EN-US_TOPIC_0000001063680582"></a>
## Overview<a name="section56901555910"></a>
After being started by the init process, the appspawn process waits for inter-process communication (IPC) messages. Upon receiving a message, the appspawn process starts an application service based on the message content, and grants the corresponding permission to the application service.
### Introduction<a name="section56901555911"></a>
- Security control
<br>Support for setting of SELinux tags for applications
- Application process control
- Support for setting of AccessToken for applications
- Support for simultaneous stopping of all spawn application processes (after stopping of the appspawn process and before a restart)
- Cold start
<br>Support for cold start of applications by using the **aa** command
```
param set appspawn.cold.boot true // Enable cold start.
aa start -d 12345 -a $name -b $package -C
Example:
aa start -d 12345 -a ohos.acts.startup.sysparam.function.MainAbility -b ohos.acts.startup.sysparam.function -C
**appspawn** is a registered service name. The appspawn process receives requests from the client by listening to messages over the local socket. The message type is an **AppProperty** structure. It is defined in **base/startup/appspawn_standard/interfaces/innerkits/include/sclient_socket.h**.
<td class="cellrowborder" valign="top" width="60.51%" headers="mcps1.2.3.1.2 "><p id="p2650329183715"><a name="p2650329183715"></a><a name="p2650329183715"></a>Name of the service process to be started. The value contains a maximum of 256 bytes.</p>
<td class="cellrowborder" valign="top" width="60.51%" headers="mcps1.2.3.1.2 "><p id="p2650329183715"><a name="p2650329183715"></a><a name="p2650329183715"></a>Bundle name of the application to be started. The value contains a maximum of 256 bytes.</p>
<td class="cellrowborder" valign="top" width="60.51%" headers="mcps1.2.3.1.2 "><p id="p13650192963715"><a name="p13650192963715"></a><a name="p13650192963715"></a>Path of the dynamic library specified by the application. The value contains a maximum of 256 bytes.</p>
<td class="cellrowborder" valign="top" width="60.51%" headers="mcps1.2.3.1.2 "><p id="p186503291371"><a name="p186503291371"></a><a name="p186503291371"></a>UID of the application process to be started. The value must be a positive number.</p>
<td class="cellrowborder" valign="top" width="60.51%" headers="mcps1.2.3.1.2 "><p id="p187716587310"><a name="p187716587310"></a><a name="p187716587310"></a>GID of the application process to be started. The value must be a positive number.</p>
<td class="cellrowborder" valign="top" width="60.51%" headers="mcps1.2.3.1.2 "><p id="p187716587310"><a name="p187716587310"></a><a name="p187716587310"></a>Information about the application process group to be started. Its length is specified by **gidCount**. A maximum of 64 process groups are supported. The value must be a positive number.</p>
<td class="cellrowborder" valign="top" width="60.51%" headers="mcps1.2.3.1.2 "><p id="p187716587310"><a name="p187716587310"></a><a name="p187716587310"></a>Number of application process groups to be started.</p>
<td class="cellrowborder" valign="top" width="60.51%" headers="mcps1.2.3.1.2 "><p id="p11650182953717"><a name="p11650182953717"></a><a name="p11650182953717"></a>Token ID for application process permission control.</p>
<td class="cellrowborder" valign="top" width="60.51%" headers="mcps1.2.3.1.2 "><p id="p11650182953717"><a name="p11650182953717"></a><a name="p11650182953717"></a> APL for application process permission control. The value contains a maximum of 32 bytes.</p>
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## Development Guidelines<a name="section56901555913"></a>
The API definitions are provided in **base/startup/appspawn_standard/interfaces/innerkits/include/client_socket.h**. Table 2 is a list of available APIs.
### Available APIs<a name="section56901555914"></a>
<td class="cellrowborder" valign="top" width="60.51%" headers="mcps1.2.3.1.2 "><p id="p186503291371"><a name="p186503291371"></a><a name="p186503291371"></a>Sends a message to the appspawn service.</p>
<td class="cellrowborder" valign="top" width="60.51%" headers="mcps1.2.3.1.2 "><p id="p187716587310"><a name="p187716587310"></a><a name="p187716587310"></a>Receives a message from the appspawn service.</p>
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### Development Example<a name="section56901555915"></a>
<br>The following is an example of using related APIs:
