/* Copyright (C) 1991-2018 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

   <http://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)