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/* Copyright (C) 1991-2020 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 <errno.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <wchar.h>
#include "libioP.h"
static void
perror_internal (FILE *fp, const char *s, int errnum)
{
char buf[1024];
const char *colon;
const char *errstring;
if (s == NULL || *s == '\0')
s = colon = "";
else
colon = ": ";
errstring = __strerror_r (errnum, buf, sizeof buf);
(void) __fxprintf (fp, "%s%s%s\n", s, colon, errstring);
}
/* Print a line on stderr consisting of the text in S, a colon, a space,
a message describing the meaning of the contents of `errno' and a newline.
If S is NULL or "", the colon and space are omitted. */
void
perror (const char *s)
{
int errnum = errno;
FILE *fp;
int fd = -1;
/* The standard says that 'perror' must not change the orientation
of the stream. What is supposed to happen when the stream isn't
oriented yet? In this case we'll create a new stream which is
using the same underlying file descriptor. */
if (__builtin_expect (_IO_fwide (stderr, 0) != 0, 1)
|| (fd = __fileno (stderr)) == -1
|| (fd = __dup (fd)) == -1
|| (fp = fdopen (fd, "w+")) == NULL)
{
if (__glibc_unlikely (fd != -1))
__close (fd);
/* Use standard error as is. */
perror_internal (stderr, s, errnum);
}
else
{
/* We don't have to do any special hacks regarding the file
position. Since the stderr stream wasn't used so far we just
write to the descriptor. */
perror_internal (fp, s, errnum);
if (_IO_ferror_unlocked (fp))
stderr->_flags |= _IO_ERR_SEEN;
/* Close the stream. */
fclose (fp);
}
}
libc_hidden_def (perror)
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