1 /* Duplicate an open file descriptor to a specified file descriptor.
3 Copyright (C) 1999, 2004, 2005, 2006, 2007, 2009 Free Software
6 This program is free software: you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>. */
19 /* written by Paul Eggert */
29 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
30 /* Get declarations of the Win32 API functions. */
31 # define WIN32_LEAN_AND_MEAN
40 rpl_dup2 (int fd, int desired_fd)
43 # if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
44 /* If fd is closed, mingw hangs on dup2 (fd, fd). If fd is open,
45 dup2 (fd, fd) returns 0, but all further attempts to use fd in
46 future dup2 calls will hang. */
49 if ((HANDLE) _get_osfhandle (fd) == INVALID_HANDLE_VALUE)
57 result = dup2 (fd, desired_fd);
59 /* Correct a Linux return value.
60 <http://git.kernel.org/?p=linux/kernel/git/stable/linux-2.6.30.y.git;a=commitdiff;h=2b79bc4f7ebbd5af3c8b867968f9f15602d5f802>
62 if (fd == desired_fd && result == (unsigned int) -EBADF)
70 /* Correct a cygwin 1.5.x errno value. */
71 else if (result == -1 && errno == EMFILE)
74 if (fd != desired_fd && result == desired_fd)
75 result = _gl_register_dup (fd, desired_fd);
80 #else /* !REPLACE_DUP2 */
82 /* On older platforms, dup2 did not exist. */
86 dupfd (int fd, int desired_fd)
88 int duplicated_fd = dup (fd);
89 if (duplicated_fd < 0 || duplicated_fd == desired_fd)
93 int r = dupfd (fd, desired_fd);
95 close (duplicated_fd);
103 dup2 (int fd, int desired_fd)
106 if (fd == desired_fd)
107 return fcntl (fd, F_GETFL) < 0 ? -1 : fd;
110 result = fcntl (fd, F_DUPFD, desired_fd);
112 result = dupfd (fd, desired_fd);
116 result = _gl_register_dup (fd, desired_fd);
120 #endif /* !REPLACE_DUP2 */