Update.
[glibc.git] / stdio-common / tmpnam.c
blob6b26f4fff62227d228e084e5c5254f5b33886c38
1 /* Copyright (C) 1991,1993,1996-1999,2000 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
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 Lesser General Public License for more details.
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, write to the Free
16 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
17 02111-1307 USA. */
19 #include <stdio.h>
20 #include <string.h>
22 static char tmpnam_buffer[L_tmpnam];
24 /* Generate a unique filename in P_tmpdir.
26 This function is *not* thread safe! */
27 char *
28 tmpnam (char *s)
30 /* By using two buffers we manage to be thread safe in the case
31 where S != NULL. */
32 char tmpbufmem[L_tmpnam];
33 char *tmpbuf = s ?: tmpbufmem;
35 /* In the following call we use the buffer pointed to by S if
36 non-NULL although we don't know the size. But we limit the size
37 to L_tmpnam characters in any case. */
38 if (__builtin_expect (__path_search (tmpbuf, L_tmpnam, NULL, NULL, 0),
39 0))
40 return NULL;
42 if (__builtin_expect (__gen_tempname (tmpbuf, __GT_NOCREATE), 0))
43 return NULL;
45 if (s == NULL)
46 return (char *) memcpy (tmpnam_buffer, tmpbuf, L_tmpnam);
48 return s;
51 link_warning (tmpnam,
52 "the use of `tmpnam' is dangerous, better use `mkstemp'")