1# getdtablesize.m4 serial 5
2dnl Copyright (C) 2008-2014 Free Software Foundation, Inc.
3dnl This file is free software; the Free Software Foundation
4dnl gives unlimited permission to copy and/or distribute it,
5dnl with or without modifications, as long as this notice is preserved.
6
7AC_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.
44AC_DEFUN([gl_PREREQ_GETDTABLESIZE], [:])
45