posix/sleep.c

   1 /* Copyright (C) 1991-2023 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <signal.h>
  19 #include <time.h>
  20 #include <unistd.h>
  21 #include <errno.h>
  22
  23 /* Make the process sleep for SECONDS seconds, or until a signal arrives
  24    and is not ignored.  The function returns the number of seconds less
  25    than SECONDS which it actually slept (zero if it slept the full time).
  26    If a signal handler does a `longjmp' or modifies the handling of the
  27    SIGALRM signal while inside `sleep' call, the handling of the SIGALRM
  28    signal afterwards is undefined.  There is no return value to indicate
  29    error, but if `sleep' returns SECONDS, it probably didn't work.  */
  30 unsigned int
  31 __sleep (unsigned int seconds)
  32 {
  33   __set_errno (ENOSYS);
  34   return seconds;
  35 }
  36 weak_alias (__sleep, sleep)
  37
  38 stub_warning (sleep)