stdio-common/tempnam.c

   1 /* Copyright (C) 1991, 1993, 1996 Free Software Foundation, Inc.
   2 This file is part of the GNU C Library.
   3
   4 The GNU C Library is free software; you can redistribute it and/or
   5 modify it under the terms of the GNU Library General Public License as
   6 published by the Free Software Foundation; either version 2 of the
   7 License, or (at your option) any later version.
   8
   9 The GNU C Library is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12 Library General Public License for more details.
  13
  14 You should have received a copy of the GNU Library General Public
  15 License along with the GNU C Library; see the file COPYING.LIB.  If
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 #include <errno.h>
  20 #include <stddef.h>
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24
  25
  26 /* Generate a unique temporary filename using up to five characters of PFX
  27    if it is not NULL.  The directory to put this file in is searched for
  28    as follows: First the environment variable "TMPDIR" is checked.
  29    If it contains the name of a writable directory, that directory is used.
  30    If not and if DIR is not NULL, that value is checked.  If that fails,
  31    P_tmpdir is tried and finally "/tmp".  The storage for the filename
  32    is allocated by `malloc'.  */
  33 char *
  34 tempnam (const char *dir, const char *pfx)
  35 {
  36   char buf[FILENAME_MAX];
  37   size_t len;
  38   register char *s;
  39   register char *t = __stdio_gen_tempname (buf, sizeof (buf), dir, pfx, 1,
  40                                            &len, (FILE **) NULL);
  41
  42   if (t == NULL)
  43     return NULL;
  44
  45   s = (char *) malloc (len);
  46   if (s == NULL)
  47     return NULL;
  48
  49   return (char *) memcpy (s, t, len);
  50 }