77 lines
2.5 KiB
C
77 lines
2.5 KiB
C
|
/* xnanosleep.c -- a more convenient interface to nanosleep
|
||
|
|
|
||
|
|
Copyright (C) 2002-2007, 2009-2020 Free Software Foundation, Inc.
|
||
|
|
|
||
|
|
This program is free software: you can redistribute it and/or modify
|
||
|
|
it under the terms of the GNU General Public License as published by
|
||
|
|
the Free Software Foundation; either version 3 of the License, or
|
||
|
|
(at your option) any later version.
|
||
|
|
|
||
|
|
This program is distributed in the hope that it will be useful,
|
||
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||
|
|
GNU General Public License for more details.
|
||
|
|
|
||
|
|
You should have received a copy of the GNU General Public License
|
||
|
|
along with this program. If not, see <https://www.gnu.org/licenses/>. */
|
||
|
|
|
||
|
|
/* Mostly written (for sleep.c) by Paul Eggert.
|
||
|
|
Factored out (creating this file) by Jim Meyering. */
|
||
|
|
|
||
|
|
#include <config.h>
|
||
|
|
|
||
|
|
#include "xnanosleep.h"
|
||
|
|
|
||
|
|
#include <intprops.h>
|
||
|
|
#include <timespec.h>
|
||
|
|
|
||
|
|
#include <errno.h>
|
||
|
|
#include <time.h>
|
||
|
|
#include <unistd.h>
|
||
|
|
|
||
|
|
/* Sleep until the time (call it WAKE_UP_TIME) specified as
|
||
|
|
SECONDS seconds after the time this function is called.
|
||
|
|
SECONDS must be non-negative. If SECONDS is so large that
|
||
|
|
it is not representable as a 'struct timespec', then use
|
||
|
|
the maximum value for that interval. Return -1 on failure
|
||
|
|
(setting errno), 0 on success. */
|
||
|
|
|
||
|
|
int
|
||
|
|
xnanosleep (double seconds)
|
||
|
|
{
|
||
|
|
#if HAVE_PAUSE
|
||
|
|
if (1.0 + TYPE_MAXIMUM (time_t) <= seconds)
|
||
|
|
{
|
||
|
|
do
|
||
|
|
pause ();
|
||
|
|
while (errno == EINTR);
|
||
|
|
|
||
|
|
/* pause failed (!); fall back on repeated nanosleep calls. */
|
||
|
|
}
|
||
|
|
#endif
|
||
|
|
|
||
|
|
struct timespec ts_sleep = dtotimespec (seconds);
|
||
|
|
|
||
|
|
for (;;)
|
||
|
|
{
|
||
|
|
/* Linux-2.6.8.1's nanosleep returns -1, but doesn't set errno
|
||
|
|
when resumed after being suspended. Earlier versions would
|
||
|
|
set errno to EINTR. nanosleep from linux-2.6.10, as well as
|
||
|
|
implementations by (all?) other vendors, doesn't return -1
|
||
|
|
in that case; either it continues sleeping (if time remains)
|
||
|
|
or it returns zero (if the wake-up time has passed).
|
||
|
|
|
||
|
|
Gnulib's replacement nanosleep sometimes does not update
|
||
|
|
TS_SLEEP, and it is possible some kernels have a similar bug.
|
||
|
|
However, this merely causes xnanosleep to sleep longer than
|
||
|
|
necessary, which is not a correctness bug. */
|
||
|
|
errno = 0;
|
||
|
|
if (nanosleep (&ts_sleep, &ts_sleep) == 0)
|
||
|
|
break;
|
||
|
|
if (errno != EINTR && errno != 0)
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|