lib/libasyn/asyn_cancel.c

   1 /*      asyn_cancel() - cancel an asynch operation      Author: Kees J. Bot
   2  *                                                              7 Jul 1997
   3  */
   4 #include "asyn.h"
   5
   6 int asyn_cancel(asynchio_t *asyn, int fd, int op)
   7 /* Cancel an asynchronous operation if one is in progress.  (This is easy with
   8  * select(2), because no operation is actually happening.)
   9  */
  10 {
  11         asynfd_t *afd;
  12
  13         if ((unsigned) fd >= FD_SETSIZE) { errno= EBADF; return -1; }
  14         afd= &asyn->asyn_afd[fd];
  15
  16         if (afd->afd_state[op] == WAITING) {
  17                 afd->afd_state[op]= IDLE;
  18                 FD_CLR(fd, &asyn->asyn_fdset[SEL_READ]);
  19         }
  20         return 0;
  21 }