glibc/stdio-common/tempnam.c

/* Copyright (C) 1991, 1993, 1996, 1997 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 Library General Public License as
   published by the Free Software Foundation; either version 2 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include <errno.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>


/* Generate a unique temporary filename using up to five characters of PFX
   if it is not NULL.  The directory to put this file in is searched for
   as follows: First the environment variable "TMPDIR" is checked.
   If it contains the name of a writable directory, that directory is used.
   If not and if DIR is not NULL, that value is checked.  If that fails,
   P_tmpdir is tried and finally "/tmp".  The storage for the filename
   is allocated by `malloc'.  */
char *
tempnam (const char *dir, const char *pfx)
{
  char buf[FILENAME_MAX];
  size_t len;
  char *s;
  char *t = __stdio_gen_tempname (buf, sizeof (buf), dir, pfx, 1,
				  &len, (FILE **) NULL, 0);

  if (t == NULL)
    return NULL;

  s = (char *) malloc (len);
  if (s == NULL)
    return NULL;

  return (char *) memcpy (s, t, len);
}