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Location:
e32std.h
Link against: euser.lib
RSessionBase
Supported from 5.0
Client-side handle to a session with a server.
This is the client-side interface through which communication with the server is channelled.
Clients normally define and implement a derived class to provide a richer interface.
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Defined in RSessionBase:
Attach(), CreateSession(), CreateSession(), CreateSession(), EAutoAttach, EExplicitAttach, Send(), SendReceive(), SendReceive(), SetRetry(), Share(), TAttachMode
Inherited from RHandleBase:
Close(),
Duplicate(),
Handle(),
SetHandle()
TInt Share(TAttachMode aAttachMode=EExplicitAttach);
Supported from 6.0
Makes the session shared among all threads in the process. A session is thread specific until this function is called.
If the session is with a server that does not support the sharing of sessions, a KERN-SVR 23 panic is raised.
If the session is already shared. the function has no effect.
Notes:
If explicit attach mode is specified, then a client thread
must call Attach() before attempting to send a message, otherwise
it is panicked KERN-SVR 0.
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TInt Attach() const;
Supported from 6.0
Explicitly attaches a thread to the session.
Calling this function ensures that the necessary Kernel resources are allocated to allow the thread to send messages.
Notes:
If a thread is required to explicitly attach to the session, then this function must be called before that thread can use the session.
A prior call to RSessionBase::Share() must
have been made before this function is called, otherwise a KERN_SVR 0 panic is
raised.
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protected: TInt CreateSession(const TDesC& aServer,const TVersion& aVersion);
Supported from 6.0
Creates a session with a server, specifying no message slots.
It should be called as part of session initialisation in the derived class.
Message slots are not pre-allocated for the session but are taken from a system-wide pool allowing up to 255 asynchronous messages to be outstanding. This raises a risk of failure due to lack of memory and, therefore, this mode of operation is not viable for sessions that make guarantees about the failure modes of asynchonous services.
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protected: TInt CreateSession(const TDesC& aServer,const TVersion& aVersion,TInt aAsyncMessageSlots);
Supported from 6.0
Creates a session with a server.
It should be called as part of session initialisation in the derived class.
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protected: TInt CreateSession(const TDesC& aServer,const TVersion& aVersion,TInt aMessageSlots,TTimeIntervalMicroSeconds32 aDelayTime=KSendDelayTime,TInt aRetryCount=KSendRetryCount);
Withdrawn in 6.0
Creates a session with a server.
It should be called as part of session initialisation in the derived class. A number of attributes governing the session are specified here.
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protected: void SetRetry(TTimeIntervalMicroSeconds32 aDelayTime,TInt aRetryCount);
Withdrawn in 6.0
Changes the retry parameters used to resend a message if the server is busy.
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protected: TInt Send(TInt aFunction,TAny* aPtr) const;
Sends a blind message to the server, and 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.
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protected: void SendReceive(TInt aFunction,TAny* aPtr,TRequestStatus& aStatus) const;
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.
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protected: TInt SendReceive(TInt aFunction,TAny* aPtr) const;
Sends a message to the server and waits synchronously 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 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().
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TAttachMode
Supported from 6.0
Indicates whether threads in the process are automatically attached to the session when passed as a parameter to the Share() function.
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©2002 Symbian Ltd. |
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