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resmgr_msg_again()
Process a message again in a resource manager

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        Process a message again in a resource manager
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resmgr_msg_again()

QNX SDP8.0C Library ReferenceAPIDeveloper

Process a message again in a resource manager

Synopsis:

#include <sys/iofunc.h>
#include <sys/resmgr.h>

int resmgr_msg_again( resmgr_context_t *ctp,
                      rcvid_t rcvid);

Arguments:

ctp: A pointer to a resmgr_context_t structure that the resource-manager library uses to pass context information between functions.
rcvid: The receive ID of the message that you want to process again.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The resmgr_msg_again() function reprocesses the message corresponding to the given rcvid. It does this by:

calling MsgInfo() and MsgRead() to refresh the resmgr_context_t structure to be as it was as when you originally received the message
calling MsgCurrent() to adjust your server threads' priority to that of the blocked client
processing the message as if it had just arrived

You use this function if your resource manager can't process a message right away. For example, if a read operation is blocked, your io_read handler would save the rcvid of the request, and then return _RESMGR_NOREPLY, leaving the client blocked. Later, when the resource manager can handle the request, it can call resmgr_msg_again() to reprocess the message.

Returns:

-1: Failure.
0: Success.

Errors:

EFAULT: A fault occurred when the kernel tried to access the buffers provided.
ESRCH: The thread indicated by rcvid doesn't exist, has had its connection detached, or isn't in STATE_REPLY, or it isn't blocked on the connection associated with the rcvid.
ESRVRFAULT: The receive side of a message transfer encountered a memory fault accessing the receive/reply buffer.

Classification:


Safety:
Cancellation point	No
Signal handler	No
Thread	Yes

Page updated: August 09, 2024