lib/sleep.c

   1 /* Pausing execution of the current thread.
   2    Copyright (C) 2007, 2009-2024 Free Software Foundation, Inc.
   3    Written by Bruno Haible <bruno@clisp.org>, 2007.
   4
   5    This file is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU Lesser General Public License as
   7    published by the Free Software Foundation; either version 2.1 of the
   8    License, or (at your option) any later version.
   9
  10    This file is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public License
  16    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  17
  18 #include <config.h>
  19
  20 /* Specification.  */
  21 #include <unistd.h>
  22
  23 #include <limits.h>
  24
  25 #if defined _WIN32 && ! defined __CYGWIN__
  26
  27 # define WIN32_LEAN_AND_MEAN  /* avoid including junk */
  28 # include <windows.h>
  29
  30 unsigned int
  31 sleep (unsigned int seconds)
  32 {
  33   unsigned int remaining;
  34
  35   /* Sleep for 1 second many times, because
  36        1. Sleep is not interruptible by Ctrl-C,
  37        2. we want to avoid arithmetic overflow while multiplying with 1000.  */
  38   for (remaining = seconds; remaining > 0; remaining--)
  39     Sleep (1000);
  40
  41   return remaining;
  42 }
  43
  44 #elif HAVE_SLEEP
  45
  46 # undef sleep
  47
  48 /* Guarantee unlimited sleep and a reasonable return value.  Cygwin
  49    1.5.x rejects attempts to sleep more than 49.7 days (2**32
  50    milliseconds), but uses uninitialized memory which results in a
  51    garbage answer.  Similarly, Linux 2.6.9 with glibc 2.3.4 has a too
  52    small return value when asked to sleep more than 24.85 days.  */
  53 unsigned int
  54 rpl_sleep (unsigned int seconds)
  55 {
  56   /* This requires int larger than 16 bits.  */
  57   static_assert (UINT_MAX / 24 / 24 / 60 / 60);
  58   const unsigned int limit = 24 * 24 * 60 * 60;
  59   while (limit < seconds)
  60     {
  61       unsigned int result;
  62       seconds -= limit;
  63       result = sleep (limit);
  64       if (result)
  65         return seconds + result;
  66     }
  67   return sleep (seconds);
  68 }
  69
  70 #else /* !HAVE_SLEEP */
  71
  72  #error "Please port gnulib sleep.c to your platform, possibly using usleep() or select(), then report this to bug-gnulib."
  73
  74 #endif