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/* Duplicate a file descriptor. Linux version.
Copyright (C) 2011-2025 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library 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 2.1 of the License, or (at your option) any later version.
The GNU C Library 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 the GNU C Library. If not, see
<https://www.gnu.org/licenses/>. */
#include <fcntl.h>
#include <unistd.h>
#include <sysdep.h>
/* Duplicate FD to FD2, closing the old FD2 and making FD2 be
open the same file as FD is. Return FD2 or -1. */
int
__dup2 (int fd, int fd2)
{
#ifdef __NR_dup2
return INLINE_SYSCALL_CALL (dup2, fd, fd2);
#else
/* For the degenerate case, check if the fd is valid (by trying to
get the file status flags) and return it, or else return EBADF. */
if (fd == fd2)
return __libc_fcntl (fd, F_GETFL, 0) < 0 ? -1 : fd;
return INLINE_SYSCALL_CALL (dup3, fd, fd2, 0);
#endif
}
libc_hidden_def (__dup2)
weak_alias (__dup2, dup2)
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