dispatch_context_alloc()

Return a dispatch context

Synopsis:

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

dispatch_context_t * dispatch_context_alloc
                   ( dispatch_t * dpp );

Arguments:

dpp
A dispatch handle created by a successful call to dispatch_create() .

Library:

libc

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

Description:

The dispatch_context_alloc() function returns a dispatch context pointer. The function is passed in the handle dpp from dispatch_create() . The dispatch context is used by dispatch to do its work. It's passed as an argument to dispatch_block() and dispatch_handler() .

The dispatch_context_alloc() function fails if you haven't attached any events to dispatch yet (e.g. you didn't call message_attach() , resmgr_attach() , or select_attach() ). The dispatch library can't allocate a proper context until it knows what kind of events you want to block.

Returns:

A pointer to a dispatch context, or NULL if an error occurs ( errno is set).

Errors:

EINVAL
No events were attached.
ENOMEM
Insufficient memory to allocate context.

Examples:

#include <sys/dispatch.h>
#include <stdio.h>    
#include <stdlib.h>   
    
int main( int argc, char **argv ) {
   dispatch_t           *dpp;
   dispatch_context_t   *ctp;

   if( ( dpp = dispatch_create() ) == NULL ) {
     fprintf( stderr, "%s: Unable to allocate \
              dispatch handle.\n",argv[0] );
     return EXIT_FAILURE;
   }

   &vellip;

   ctp = dispatch_context_alloc( dpp );

   &vellip;

   return EXIT_SUCCESS;
}

For examples using the dispatch interface, see dispatch_create() , message_attach() , resmgr_attach() , and thread_pool_create() .

Classification:

QNX Neutrino

Safety:  
Cancellation point No
Interrupt handler No
Signal handler No
Thread Yes

Last modified: 2013-12-23

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