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41 lines
1.4 KiB
C
41 lines
1.4 KiB
C
/* Duplicate a file descriptor. Linux version.
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Copyright (C) 2011-2023 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library. If not, see
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<https://www.gnu.org/licenses/>. */
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#include <fcntl.h>
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#include <unistd.h>
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#include <sysdep.h>
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/* Duplicate FD to FD2, closing the old FD2 and making FD2 be
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open the same file as FD is. Return FD2 or -1. */
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int
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__dup2 (int fd, int fd2)
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{
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#ifdef __NR_dup2
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return INLINE_SYSCALL_CALL (dup2, fd, fd2);
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#else
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/* For the degenerate case, check if the fd is valid (by trying to
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get the file status flags) and return it, or else return EBADF. */
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if (fd == fd2)
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return __libc_fcntl (fd, F_GETFL, 0) < 0 ? -1 : fd;
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return INLINE_SYSCALL_CALL (dup3, fd, fd2, 0);
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#endif
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}
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libc_hidden_def (__dup2)
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weak_alias (__dup2, dup2)
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