freebsd-src/lib/libncurses/lib_twait.c
1994-12-02 06:40:24 +00:00

76 lines
1.8 KiB
C

/* This work is copyrighted. See COPYRIGHT.OLD & COPYRIGHT.NEW for *
* details. If they are missing then this copy is in violation of *
* the copyright conditions. */
/*
** lib_twait.c
**
** The routine timed_wait().
**
*/
#include <string.h>
#include <sys/types.h> /* some systems can't live without this */
#include <sys/time.h>
#include <unistd.h>
#if defined(SYS_SELECT)
#include <sys/select.h>
#endif
#include "curses.priv.h"
#if defined(NOUSLEEP)
void usleep(unsigned int usec)
{
struct timeval tval;
tval.tv_sec = usec / 1000000;
tval.tv_usec = usec % 1000000;
select(0, NULL, NULL, NULL, &tval);
}
#endif
int timed_wait(int fd, int wait, int *timeleft)
{
int result;
struct timeval timeout;
static fd_set set;
#ifndef GOOD_SELECT
struct timeval starttime, returntime;
gettimeofday(&starttime, NULL);
#endif
FD_ZERO(&set);
FD_SET(fd, &set);
/* the units of wait are milliseconds */
timeout.tv_sec = wait / 1000;
timeout.tv_usec = (wait % 1000) * 1000;
T(("start twait: sec = %d, usec = %d", timeout.tv_sec, timeout.tv_usec));
result = select(fd+1, &set, NULL, NULL, &timeout);
#ifndef GOOD_SELECT
gettimeofday(&returntime, NULL);
timeout.tv_sec -= (returntime.tv_sec - starttime.tv_sec);
timeout.tv_usec -= (returntime.tv_usec - starttime.tv_usec);
if (timeout.tv_usec < 0 && timeout.tv_sec > 0) {
timeout.tv_sec--;
timeout.tv_usec += 1000000;
}
if (timeout.tv_sec < 0)
timeout.tv_sec = timeout.tv_usec = 0;
#endif
/* return approximate time left on the timeout, in milliseconds */
if (timeleft)
*timeleft = (timeout.tv_sec * 1000) + (timeout.tv_usec / 1000);
T(("end twait: returned %d, sec = %d, usec = %d (%d msec)",
result, timeout.tv_sec, timeout.tv_usec, *timeleft));
return(result);
}