stdio-common/tempnam.c

   1 /* Copyright (C) 1991, 1993 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 <ansidecl.h>
  20 #include <errno.h>
  21 #include <stddef.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25
  26
  27 /* Generate a unique temporary filename using up to five characters of PFX
  28    if it is not NULL.  The directory to put this file in is searched for
  29    as follows: First the environment variable "TMPDIR" is checked.
  30    If it contains the name of a writable directory, that directory is used.
  31    If not and if DIR is not NULL, that value is checked.  If that fails,
  32    P_tmpdir is tried and finally "/tmp".  The storage for the filename
  33    is allocated by `malloc'.  */
  34 char *
  35 DEFUN(tempnam, (dir, pfx), CONST char *dir AND CONST char *pfx)
  36 {
  37   size_t len;
  38   register char *s;
  39   register char *t = __stdio_gen_tempname(dir, pfx, 1, &len, (FILE **) NULL);
  40
  41   if (t == NULL)
  42     return NULL;
  43
  44   s = (char *) malloc(len);
  45   if (s == NULL)
  46     return NULL;
  47
  48   (void) memcpy(s, t, len);
  49   return s;
  50 }