1/* Copyright (C) 1991-2022 Free Software Foundation, Inc.
2
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library 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 GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <unistd.h>
20
21/* Duplicate FD to FD2, closing the old FD2 and making FD2 be
22 open on the same file as FD is. Return FD2 or -1. */
23int
24__dup2 (int fd, int fd2)
25{
26 int flags = 0;
27
28 if (fd2 == fd)
29 /* See the comment in dup3. */
30 flags = -1;
31
32 return __dup3 (fd, fd2, flags);
33}
34libc_hidden_def (__dup2)
35weak_alias (__dup2, dup2)
36

source code of glibc/sysdeps/mach/hurd/dup2.c