Updated: October 28, 2024 |
Send notifications to queued clients
#include <sys/iofunc.h> void iofunc_notify_trigger( iofunc_notify_t *nop, int count, int index ); void iofunc_notify_trigger_strict( resmgr_context_t *ctp, iofunc_notify_t *nop, int count, int index );
libc
Use the -l c option to qcc to link against this library. This library is usually included automatically.
The iofunc_notify_trigger() function examines all entries given in the list at nop[index] to see if each event should be delivered. If the specified count is greater than or equal to the trigger value for the particular notification list element, then the function updates the event if appropriate, calls MsgDeliverEvent() to deliver the event to the client whose rcvid is stored in that list element, and disarms the element.
The iofunc_notify_trigger_strict() function is similar, except that only notifications armed via the file descriptor in the client that maps to the ctp argument are notified. The strict variant is useful when a duplicated file descriptor is closed, and only clients blocked on that descriptor are required to wake up and notice (EBADF on subsequent read or write). Calling this function with a ctp of NULL provides the same behavior as iofunc_notify_trigger().
A resource manager generally calls iofunc_notify_trigger_strict() in a close_dup callout to unblock any client poll() calls that are waiting on a file descriptor that's been closed. You should call it three times with a count value of INT_MAX, the ctp passed to the close_dup callout, and an index of IOFUNC_NOTIFY_INPUT, IOFUNC_NOTIFY_OUTPUT, and IOFUNC_NOTIFY_OBAND.
#define IOFUNC_NOTIFY_INPUT_CHECK(__nop, __cnt, __tran) ... #define IOFUNC_NOTIFY_OUTPUT_CHECK(__nop, __cnt) ... #define IOFUNC_NOTIFY_OBAND_CHECK(__nop, __cnt, __tran) ...
The arguments are:
Safety: | |
---|---|
Cancellation point | No |
Interrupt handler | No |
Signal handler | Yes |
Thread | Read the Caveats |
To ensure thread safety, lock the underlying object before calling this function. This object is usually an iofunc_attr_t structure; lock it by calling iofunc_attr_lock().