# message.h ## **Overview** **Related Modules:** [Samgr](Samgr.md) **Description:** Provides message communication APIs that help you to implement asynchronous functions of [IUnknown](IUnknown.md). This API is used to implement asynchronous functions of [IUnknown](IUnknown.md). **Since:** 1.0 **Version:** 1.0 ## **Summary** ## Data Structures

Data Structure Name	Description
Identity	Identifies a service and feature.
Request	Defines a request.
Response	Defines a response.

## Typedefs

Typedef Name	Description
Handler) (const Request request, const Response response)	typedef void(* Handles asynchronous responses.

Typedef Name

Description

Handler) (const Request *request, const Response *response)

typedef void(*

Handles asynchronous responses.

## Functions

Function Name	Description
SAMGR_SendRequest (const Identity identity, const Request request, Handler handler)	int32 Sends a request to a service or feature of a specified identity.
SAMGR_SendSharedRequest (const Identity identity, const Request request, uint32 *token, Handler handler)	uint32 * Sends a request to multiple services or features to save memory.
SAMGR_SendSharedDirectRequest (const Identity id, const Request req, const Response resp, uint32 *ref, Handler handler)	int32 Sends a request and response of a caller to the feature thread. The handler is directly called to process the request and response without using the message processing functions. (Customized function for the broadcast service)
SAMGR_SendResponse (const Request request, const Response response)	int32 Sends a response after processing a request.
SAMGR_SendResponseByIdentity (const Identity id, const Request request, const Response *response)	int32 Sends a response to a specified service or feature after processing the original request. (Customized function for bootstrap)