stdio-common/tmpfile.c

   1 /* Open a stdio stream on an anonymous temporary file.  Generic/POSIX version.
   2    Copyright (C) 1991,93,1996-2000,2002,2003 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <stdio.h>
  21 #include <unistd.h>
  22
  23 #ifdef USE_IN_LIBIO
  24 # include <iolibio.h>
  25 # define __fdopen INTUSE(_IO_fdopen)
  26 # ifndef tmpfile
  27 #  define tmpfile __new_tmpfile
  28 # endif
  29 #endif
  30
  31 #ifndef GEN_THIS
  32 # define GEN_THIS __GT_FILE
  33 #endif
  34
  35 /* This returns a new stream opened on a temporary file (generated
  36    by tmpnam).  The file is opened with mode "w+b" (binary read/write).
  37    If we couldn't generate a unique filename or the file couldn't
  38    be opened, NULL is returned.  */
  39 FILE *
  40 tmpfile (void)
  41 {
  42   char buf[FILENAME_MAX];
  43   int fd;
  44   FILE *f;
  45
  46   if (__path_search (buf, FILENAME_MAX, NULL, "tmpf", 0))
  47     return NULL;
  48   fd = __gen_tempname (buf, GEN_THIS);
  49   if (fd < 0)
  50     return NULL;
  51
  52   /* Note that this relies on the Unix semantics that
  53      a file is not really removed until it is closed.  */
  54   (void) __unlink (buf);
  55
  56   if ((f = __fdopen (fd, "w+b")) == NULL)
  57     __close (fd);
  58
  59   return f;
  60 }
  61
  62 #if defined USE_IN_LIBIO && GEN_THIS == __GT_FILE /* Not for tmpfile64.  */
  63 # undef tmpfile
  64 # include <shlib-compat.h>
  65 versioned_symbol (libc, __new_tmpfile, tmpfile, GLIBC_2_1);
  66 #endif