Class RSubSessionBase

RSubSessionBase

Support

Supported from 5.0

Description

Client-side handle to a sub-session.

It represents a client-side sub-session and has a corresponding sub-session object on the server-side.

Clients normally define and implement a derived class to provide a richer interface. In particular, a derived class should:

• provide a function to create a new sub-session with the server; this should call CreateSubSession().

• provide a function to close the current sub-session; this should call CloseSubSession().

A session must already exist with a server before a client can establish any sub-sessions.

Defined in RSubSessionBase:
CloseSubSession(), CreateSubSession(), RSubSessionBase(), RSubSessionBase(), Send(), SendReceive(), SendReceive(), SubSessionHandle(), operator=()

See also:

• RSubSessionBase::CreateSubSession()
• RSubSessionBase::CloseSubSession()

protected: RSubSessionBase();

Description

Constructs a default sub-session object.

protected: RSubSessionBase(const RSubSessionBase& aSubSession);

Description

Copy constructor.

Parameters

protected: RSubSessionBase& operator=(const RSubSessionBase& aSubSession);

Description

Assignment constructor.

Parameters

Return value

protected: TInt CreateSubSession(RSessionBase& aSession,TInt aFunction,const TAny* aPtr);

Description

Creates a new sub-session within an existing session.

Parameters

Return value

protected: void CloseSubSession(TInt aFunction);

Description

Closes the sub-session.

Parameters

protected: TInt Send(TInt aFunction,const TAny* aPtr) const;

Description

Sends a blind message to the server — no reply is expected. A message argument array is passed; this may be used to specify client addresses which the server can use to read from and write to the client address space.

Note that this function can fail if there are no available message-slots, either in the system wide pool (if this is being used), or in the session reserved pool (if this is being used). If the client request is synchronous, then always use the synchronous variant of SendReceive(); this is guaranteed to reach the server.

Parameters

Return value

protected: void SendReceive(TInt aFunction,const TAny* aPtr,TRequestStatus& aStatus) const;

Description

Sends a message to the server and waits asynchronously for the reply. An opcode specifies the service required. A message argument array is passed; this may be used to specify client addresses which the server can use to read from and write to the client address space.

Note that this function can fail if there are no available message-slots, either in the system wide pool (if this is being used), or in the session reserved pool (if this is being used). If the client request is synchronous, then always use the synchronous variant of SendReceive(); this is guaranteed to reach the server.

Parameters

protected: TInt SendReceive(TInt aFunction,const TAny* aPtr) const;

Description

Sends a message to the server and waits synchronously for a reply. An opcode specifies the service required. A message argument array is passed; this may be used to specify client addresses which the server can use to read from and write to the client address space.

Note that this function will only fail if the server itself fails or environmental errors occur in the server. All requests made using this function are guaranteed to reach the server. This means that all synchronous client requests (typically those that return void) should be routed through this synchronous variant of SendReceive().

Parameters

Return value

TInt SubSessionHandle();

Description

Returns the sub-session handle number.

This number is automatically passed to the server when making requests and is used to identify the appropriate server-side sub-session.

Return value