1 /* Duplicate an open file descriptor to a specified file descriptor.
3 Copyright (C) 1999, 2004-2007, 2009-2010 Free Software Foundation, Inc.
5 This program is free software: you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 3 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>. */
18 /* written by Paul Eggert */
28 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
29 /* Get declarations of the Win32 API functions. */
30 # define WIN32_LEAN_AND_MEAN
39 rpl_dup2 (int fd, int desired_fd)
42 # if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
43 /* If fd is closed, mingw hangs on dup2 (fd, fd). If fd is open,
44 dup2 (fd, fd) returns 0, but all further attempts to use fd in
45 future dup2 calls will hang. */
48 if ((HANDLE) _get_osfhandle (fd) == INVALID_HANDLE_VALUE)
56 result = dup2 (fd, desired_fd);
58 /* Correct a Linux return value.
59 <http://git.kernel.org/?p=linux/kernel/git/stable/linux-2.6.30.y.git;a=commitdiff;h=2b79bc4f7ebbd5af3c8b867968f9f15602d5f802>
61 if (fd == desired_fd && result == (unsigned int) -EBADF)
69 /* Correct a cygwin 1.5.x errno value. */
70 else if (result == -1 && errno == EMFILE)
73 if (fd != desired_fd && result != -1)
74 result = _gl_register_dup (fd, result);
79 #else /* !HAVE_DUP2 */
81 /* On older platforms, dup2 did not exist. */
85 dupfd (int fd, int desired_fd)
87 int duplicated_fd = dup (fd);
88 if (duplicated_fd < 0 || duplicated_fd == desired_fd)
92 int r = dupfd (fd, desired_fd);
94 close (duplicated_fd);
102 dup2 (int fd, int desired_fd)
104 int result = fcntl (fd, F_GETFL) < 0 ? -1 : fd;
105 if (result == -1 || fd == desired_fd)
109 result = fcntl (fd, F_DUPFD, desired_fd);
112 result = _gl_register_dup (fd, result);
115 result = dupfd (fd, desired_fd);
117 if (result == -1 && (errno == EMFILE || errno == EINVAL))
121 #endif /* !HAVE_DUP2 */