Feature.md

# Feature
## **Overview**
**Related Modules:**
[Samgr](Samgr.md)
**Description:**
Defines the base class of a feature.
You need to implement the pointer to the feature.
**Since:**
1.0
**Version:**
1.0
## **Summary**
## Data Fields

Variable Name	Description
GetName )(Feature *feature)	const char *(*  Obtains a feature name.
OnInitialize )(Feature *feature, Service *parent, Identity identity)	void(*  Initializes a feature.
OnStop )(Feature *feature, Identity identity)	void(*  Stops a feature.
OnMessage )(Feature *feature, Request *request)	BOOL(*  Processes a feature message.

## **Details**
## **Field Documentation**
## GetName
```
const char*(* Feature::GetName) ([Feature](Feature.md) *feature)
```
**Description:**
Obtains a feature name.
This function is implemented by developers and called by Samgr during feature registration and startup.
**Parameters:**

Name	Description
feature	Indicates the pointer to the feature.

**Returns:**
Returns a constant character string less than 16 bytes if the operation is successful; returns **NULL** if the operation fails.
## OnInitialize
```
void(* Feature::OnInitialize) ([Feature](Feature.md) *feature, [Service](Service.md) *parent, [Identity](Identity.md) identity)
```
**Description:**
Initializes a feature.
This function is implemented by developers. After Samgr dispatches tasks to a service, the service calls this function in its own tasks.
**Parameters:**

Name	Description
feature	Indicates the pointer to the feature.
parent	Indicates the pointer to the Service to which the feature belongs.
identity	Indicates the identity of a feature dispatched by the system.

## OnMessage
```
BOOL(* Feature::OnMessage) ([Feature](Feature.md) *feature, [Request](Request.md) *request)
```
**Description:**
Processes a feature message.
This function is implemented by developers to process requests sent by callers through [IUnknown](IUnknown.md).
**Parameters:**

Name	Description
feature	Indicates the pointer to the feature.
request	Indicates the request message.

**Returns:**
Returns **TRUE** if the processing is successful; returns **FALSE** if the processing fails.
## OnStop
```
void(* Feature::OnStop) ([Feature](Feature.md) *feature, [Identity](Identity.md) identity)
```
**Description:**
Stops a feature.
This function is implemented by developers and is called by Samgr when a feature is deregistered to stop running services.
**Parameters:**

Name	Description
feature	Indicates the pointer to the feature.
identity	Indicates the Identity of the feature to be stopped.