xapian-core/common/safeunistd.h

   1 /** @file safeunistd.h
   2  * @brief <unistd.h>, but with compat. and large file support for MSVC.
   3  */
   4 /* Copyright (C) 2007,2015 Olly Betts
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License as
   8  * published by the Free Software Foundation; either version 2 of the
   9  * License, or (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301
  19  * USA
  20  */
  21
  22 #ifndef XAPIAN_INCLUDED_SAFEUNISTD_H
  23 #define XAPIAN_INCLUDED_SAFEUNISTD_H
  24
  25 #ifndef _MSC_VER
  26 # include <unistd.h>
  27 #else
  28
  29 // sys/types.h has a typedef for off_t so make sure we've seen that before
  30 // we hide it behind a #define.
  31 # include <sys/types.h>
  32
  33 // MSVC doesn't even HAVE unistd.h - io.h seems the nearest equivalent.
  34 // We also need to do some renaming of functions to get versions which
  35 // work on large files.
  36 # include <io.h>
  37
  38 # ifdef lseek
  39 #  undef lseek
  40 # endif
  41
  42 # ifdef off_t
  43 #  undef off_t
  44 # endif
  45
  46 # define lseek(FD, OFF, WHENCE) _lseeki64(FD, OFF, WHENCE)
  47 # define off_t __int64
  48
  49 // process.h is needed for getpid().
  50 # include <process.h>
  51
  52 #endif
  53
  54 // Under mingw we probably don't need to provide our own sleep().
  55 #if defined __WIN32__ && !defined HAVE_SLEEP
  56
  57 inline unsigned int
  58 sleep(unsigned int seconds)
  59 {
  60     // Use our own little helper function to avoid pulling in <windows.h>.
  61     extern void xapian_sleep_milliseconds(unsigned int millisecs);
  62
  63     // Sleep takes a time interval in milliseconds, whereas POSIX sleep takes
  64     // a time interval in seconds, so we need to multiply 'seconds' by 1000.
  65     //
  66     // But make sure the multiplication won't overflow!  4294967 seconds is
  67     // nearly 50 days, so just sleep for that long and return the number of
  68     // seconds left to sleep for.  The common case of sleep(CONSTANT) should
  69     // optimise to just xapian_sleep_milliseconds(CONSTANT).
  70     if (seconds > 4294967u) {
  71         xapian_sleep_milliseconds(4294967000u);
  72         return seconds - 4294967u;
  73     }
  74     xapian_sleep_milliseconds(seconds * 1000u);
  75     return 0;
  76 }
  77
  78 #endif
  79
  80 #endif /* XAPIAN_INCLUDED_SAFEUNISTD_H */