lib/sleep.c

   1 /* Pausing execution of the current thread.
   2    Copyright (C) 2007, 2009-2021 Free Software Foundation, Inc.
   3    Written by Bruno Haible <bruno@clisp.org>, 2007.
   4
   5    This program is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program 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 General Public License for more details.
  14
  15    You should have received a copy of the GNU 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 #include "verify.h"
  26
  27 #if defined _WIN32 && ! defined __CYGWIN__
  28
  29 # define WIN32_LEAN_AND_MEAN  /* avoid including junk */
  30 # include <windows.h>
  31
  32 unsigned int
  33 sleep (unsigned int seconds)
  34 {
  35   unsigned int remaining;
  36
  37   /* Sleep for 1 second many times, because
  38        1. Sleep is not interruptible by Ctrl-C,
  39        2. we want to avoid arithmetic overflow while multiplying with 1000.  */
  40   for (remaining = seconds; remaining > 0; remaining--)
  41     Sleep (1000);
  42
  43   return remaining;
  44 }
  45
  46 #elif HAVE_SLEEP
  47
  48 # undef sleep
  49
  50 /* Guarantee unlimited sleep and a reasonable return value.  Cygwin
  51    1.5.x rejects attempts to sleep more than 49.7 days (2**32
  52    milliseconds), but uses uninitialized memory which results in a
  53    garbage answer.  Similarly, Linux 2.6.9 with glibc 2.3.4 has a too
  54    small return value when asked to sleep more than 24.85 days.  */
  55 unsigned int
  56 rpl_sleep (unsigned int seconds)
  57 {
  58   /* This requires int larger than 16 bits.  */
  59   verify (UINT_MAX / 24 / 24 / 60 / 60);
  60   const unsigned int limit = 24 * 24 * 60 * 60;
  61   while (limit < seconds)
  62     {
  63       unsigned int result;
  64       seconds -= limit;
  65       result = sleep (limit);
  66       if (result)
  67         return seconds + result;
  68     }
  69   return sleep (seconds);
  70 }
  71
  72 #else /* !HAVE_SLEEP */
  73
  74  #error "Please port gnulib sleep.c to your platform, possibly using usleep() or select(), then report this to bug-gnulib."
  75
  76 #endif