minix3/lib/libasyn/asyn_cancel.c

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2020-02-21 00:59:27 +05:30
/* asyn_cancel() - cancel an asynch operation Author: Kees J. Bot
* 7 Jul 1997
*/
#include "asyn.h"
int asyn_cancel(asynchio_t *asyn, int fd, int op)
/* Cancel an asynchronous operation if one is in progress. (This is easy with
* select(2), because no operation is actually happening.)
*/
{
asynfd_t *afd;
if ((unsigned) fd >= FD_SETSIZE) { errno= EBADF; return -1; }
afd= &asyn->asyn_afd[fd];
if (afd->afd_state[op] == WAITING) {
afd->afd_state[op]= IDLE;
FD_CLR(fd, &asyn->asyn_fdset[SEL_READ]);
}
return 0;
}