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Jim Meyering 1999-05-01 04:15:09 +00:00
parent 6161d60dde
commit 9a06759937
1 changed files with 66 additions and 0 deletions
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lib/dup2.c Normal file
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/* Duplicate an open file descriptor to a specified file descriptor.
Copyright 1999 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software Foundation,
Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
/* written by Paul Eggert */
#if HAVE_CONFIG_H
# include <config.h>
#endif
#include <errno.h>
#ifndef errno
extern int errno;
#endif
#if HAVE_FCNTL_H
# include <fcntl.h>
#endif
#if HAVE_UNISTD_H
# include <unistd.h>
#endif
#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
}