| /* 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; |
| } |