Allocate a dispatch structure, specifying a channel ID
#include <sys/iofunc.h> #include <sys/dispatch.h> dispatch_t *dispatch_create_channel( int chid, unsigned flags );
libc
Use the -l c option to qcc to link against this library. This library is usually included automatically.
The dispatch_create_channel() function allocates and initializes a dispatch structure, and returns a handle to this structure. This function is similar to dispatch_create(), but lets you specify a channel. This is useful if you want to control the channel for name_attach() or resmgr_attach(). For example, if you wanted two or more names to the same channel, or if you wanted non-default channel flags.
After you've called this function, you need to call one or more of the following functions to attach handlers for the things you want the dispatch layer to deal with:
Then you call dispatch_context_alloc() to allocate the context for dispatch_block() and dispatch_handler().
If the dispatch structure is for use in a resource manager, meaning you will later call resmgr_attach() with the associated dispatch handle, then at least the flags _NTO_CHF_UNBLOCK and _NTO_CHF_DISCONNECT should be set for the supplied channel to ensure proper resource manager behavior.
If you wish, you can do a resmgr_attach() with a NULL path. This has the effect of initializing the dispatch structure to receive messages, among other things.
The dispatch_create_channel() function is part of the dispatch layer of a resource manager. For more information, see Layers in a resource manager in the The Bones of a Resource Manager chapter of Writing a Resource Manager.
A handle to a dispatch structure, or NULL if an error occurred (errno is set). The dispatch_t structure is an opaque data type; you can't access its contents directly.
Safety: | |
---|---|
Cancellation point | No |
Interrupt handler | No |
Signal handler | No |
Thread | Yes |