Symbian
Symbian OS Library

SYMBIAN OS V9.3

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Sessions and requests

Communication between client and server is represented by a session; this is initiated by the client. A client thread may have several sessions with a server. A session can also be shared by all the client threads in a process, if supported by the server, and also by all threads across all processes, again if supported by the server.

Sessions are maintained by the Kernel and the important points are:

If a call to the client interface requires a service from the server, the client interface must set up and send a message. The message has a 32-bit operation code to identify the request, and up to four 32-bit parameters. The message is encapsulated within a TIpcArgs object. The process can be summarised as follows:

The client/server framework also supports the sending of requests asynchronously to the server.

The following diagram illustrates this:

A server can support multiple connections from a client in a number of distinct ways:

A server can support the creation of sharable sessions allowing either all the threads in a client process to share a single session, or allowing all threads across all processes to share a single session. The important points are:


See also

Subsessions within a session