m4/getdtablesize.m4

   1 # getdtablesize.m4 serial 5
   2 dnl Copyright (C) 2008-2014 Free Software Foundation, Inc.
   3 dnl This file is free software; the Free Software Foundation
   4 dnl gives unlimited permission to copy and/or distribute it,
   5 dnl with or without modifications, as long as this notice is preserved.
   6
   7 AC_DEFUN([gl_FUNC_GETDTABLESIZE],
   8 [
   9   AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
  10   AC_REQUIRE([AC_CANONICAL_HOST])
  11   AC_CHECK_FUNCS_ONCE([getdtablesize])
  12   if test $ac_cv_func_getdtablesize = yes; then
  13     # Cygwin 1.7.25 automatically increases the RLIMIT_NOFILE soft limit
  14     # up to an unchangeable hard limit; all other platforms correctly
  15     # require setrlimit before getdtablesize() can report a larger value.
  16     AC_CACHE_CHECK([whether getdtablesize works],
  17       [gl_cv_func_getdtablesize_works],
  18       [AC_RUN_IFELSE([
  19         AC_LANG_PROGRAM([[#include <unistd.h>]],
  20           [int size = getdtablesize();
  21            if (dup2 (0, getdtablesize()) != -1)
  22              return 1;
  23            if (size != getdtablesize())
  24              return 2;
  25           ])],
  26         [gl_cv_func_getdtablesize_works=yes],
  27         [gl_cv_func_getdtablesize_works=no],
  28         [case "$host_os" in
  29           cygwin*) # on cygwin 1.5.25, getdtablesize() automatically grows
  30             gl_cv_func_getdtablesize_works="guessing no" ;;
  31           *) gl_cv_func_getdtablesize_works="guessing yes" ;;
  32          esac])
  33       ])
  34     case "$gl_cv_func_getdtablesize_works" in
  35       *yes) ;;
  36       *) REPLACE_GETDTABLESIZE=1 ;;
  37     esac
  38   else
  39     HAVE_GETDTABLESIZE=0
  40   fi
  41 ])
  42
  43 # Prerequisites of lib/getdtablesize.c.
  44 AC_DEFUN([gl_PREREQ_GETDTABLESIZE], [:])