1 /* -*- buffer-read-only: t -*- vi: set ro: */
2 /* DO NOT EDIT! GENERATED AUTOMATICALLY! */
3 /* getdtablesize() function for platforms that don't have it.
4 Copyright (C) 2008-2013 Free Software Foundation, Inc.
5 Written by Bruno Haible <bruno@clisp.org>, 2008.
7 This program is free software: you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
25 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
29 #include "msvc-inval.h"
31 #if HAVE_MSVC_INVALID_PARAMETER_HANDLER
33 _setmaxstdio_nothrow (int newmax)
39 result = _setmaxstdio (newmax);
49 # define _setmaxstdio _setmaxstdio_nothrow
52 /* Cache for the previous getdtablesize () result. */
53 static int dtablesize;
60 /* We are looking for the number N such that the valid file descriptors
61 are 0..N-1. It can be obtained through a loop as follows:
64 for (fd = 3; fd < 65536; fd++)
65 if (dup2 (0, fd) == -1)
69 On Windows XP, the result is 2048.
70 The drawback of this loop is that it allocates memory for a libc
71 internal array that is never freed.
73 The number N can also be obtained as the upper bound for
74 _getmaxstdio (). _getmaxstdio () returns the maximum number of open
75 FILE objects. The sanity check in _setmaxstdio reveals the maximum
76 number of file descriptors. This too allocates memory, but it is
77 freed when we call _setmaxstdio with the original value. */
78 int orig_max_stdio = _getmaxstdio ();
80 for (bound = 0x10000; _setmaxstdio (bound) < 0; bound = bound / 2)
82 _setmaxstdio (orig_max_stdio);