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) 2008-2014 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. Safe to cache because
53 Windows also lacks setrlimit. */
54 static int dtablesize;
61 /* We are looking for the number N such that the valid file descriptors
62 are 0..N-1. It can be obtained through a loop as follows:
65 for (fd = 3; fd < 65536; fd++)
66 if (dup2 (0, fd) == -1)
70 On Windows XP, the result is 2048.
71 The drawback of this loop is that it allocates memory for a libc
72 internal array that is never freed.
74 The number N can also be obtained as the upper bound for
75 _getmaxstdio (). _getmaxstdio () returns the maximum number of open
76 FILE objects. The sanity check in _setmaxstdio reveals the maximum
77 number of file descriptors. This too allocates memory, but it is
78 freed when we call _setmaxstdio with the original value. */
79 int orig_max_stdio = _getmaxstdio ();
81 for (bound = 0x10000; _setmaxstdio (bound) < 0; bound = bound / 2)
83 _setmaxstdio (orig_max_stdio);
89 #elif HAVE_GETDTABLESIZE
91 # include <sys/resource.h>
95 rpl_getdtablesize(void)
97 /* To date, this replacement is only compiled for Cygwin 1.7.25,
98 which auto-increased the RLIMIT_NOFILE soft limit until it
99 hits the compile-time constant hard limit of 3200. Although
100 that version of cygwin supported a child process inheriting
101 a smaller soft limit, the smaller limit is not enforced, so
102 we might as well just report the hard limit. */
104 if (!getrlimit (RLIMIT_NOFILE, &lim) && lim.rlim_max != RLIM_INFINITY)
106 return getdtablesize ();