Return a dispatch context
#include <sys/iofunc.h> #include <sys/dispatch.h> dispatch_context_t * dispatch_context_alloc ( dispatch_t * dpp );
libc
Use the -l c option to qcc to link against this library. This library is usually included automatically.
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. |
This function is part of the dispatch layer of a resource manager. For more information, see “Layers in a resource manager” in the Bones of a Resource Manager chapter of Writing a Resource Manager.
A pointer to a dispatch context, or NULL if an error occurs (errno is set).
#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; } ⋮ ctp = dispatch_context_alloc( dpp ); ⋮ return EXIT_SUCCESS; }
For examples using the dispatch interface, see dispatch_create(), message_attach(), resmgr_attach(), and thread_pool_create().
Safety: | |
---|---|
Cancellation point | No |
Interrupt handler | No |
Signal handler | No |
Thread | Yes |
dispatch_block(), dispatch_context_free(), dispatch_create(), dispatch_create_channel(), dispatch_handler(), dispatch_unblock()
“Layers in a resource manager” in the Bones of a Resource Manager chapter of Writing a Resource Manager