stdio-common/tmpfile.c

   1 /* Copyright (C) 1991, 1993, 1996, 1997, 1998 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 not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 #include <stdio.h>
  20 #include <unistd.h>
  21
  22 #ifdef _USE_IN_LIBIO
  23 # define fdopen _IO_new_fdopen
  24 #endif
  25
  26 /* This returns a new stream opened on a temporary file (generated
  27    by tmpnam) The file is opened with mode "w+b" (binary read/write).
  28    If we couldn't generate a unique filename or the file couldn't
  29    be opened, NULL is returned.  */
  30 FILE *
  31 tmpfile ()
  32 {
  33   char buf[FILENAME_MAX];
  34   int fd;
  35   FILE *f;
  36
  37   if (__path_search (buf, FILENAME_MAX, NULL, "tmpf"))
  38     return NULL;
  39   if ((fd = __gen_tempname (buf, 1, 0)) < 0)
  40     return NULL;
  41
  42   /* Note that this relies on the Unix semantics that
  43      a file is not really removed until it is closed.  */
  44   (void) remove (buf);
  45
  46   if ((f = fdopen (fd, "w+b")) == NULL)
  47     close (fd);
  48
  49   return f;
  50 }