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/* Duplicate an open file descriptor to a specified file descriptor.
Copyright (C) 1999, 2004, 2005, 2006, 2007, 2009 Free Software
Foundation, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
/* written by Paul Eggert */
#include <config.h>
/* Specification. */
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
/* Get declarations of the Win32 API functions. */
# define WIN32_LEAN_AND_MEAN
# include <windows.h>
#endif
#if REPLACE_DUP2
# undef dup2
int
rpl_dup2 (int fd, int desired_fd)
{
int result;
# if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
/* If fd is closed, mingw hangs on dup2 (fd, fd). If fd is open,
dup2 (fd, fd) returns 0, but all further attempts to use fd in
future dup2 calls will hang. */
if (fd == desired_fd)
{
if ((HANDLE) _get_osfhandle (fd) == INVALID_HANDLE_VALUE)
{
errno = EBADF;
return -1;
}
return fd;
}
# endif
result = dup2 (fd, desired_fd);
if (result == 0)
result = desired_fd;
return result;
}
#else /* !REPLACE_DUP2 */
/* On older platforms, dup2 did not exist. */
# ifndef F_DUPFD
static int
dupfd (int fd, int desired_fd)
{
int duplicated_fd = dup (fd);
if (duplicated_fd < 0 || duplicated_fd == desired_fd)
return duplicated_fd;
else
{
int r = dupfd (fd, desired_fd);
int e = errno;
close (duplicated_fd);
errno = e;
return r;
}
}
# endif
int
dup2 (int fd, int desired_fd)
{
if (fd == desired_fd)
return fd;
close (desired_fd);
# ifdef F_DUPFD
return fcntl (fd, F_DUPFD, desired_fd);
# else
return dupfd (fd, desired_fd);
# endif
}
#endif /* !REPLACE_DUP2 */
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