tmpnam.c 1.6 KB

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  1. /* Copyright (C) 1991,1993,1996-1999,2000 Free Software Foundation, Inc.
  2. This file is part of the GNU C Library.
  3. The GNU C Library is free software; you can redistribute it and/or
  4. modify it under the terms of the GNU Lesser General Public
  5. License as published by the Free Software Foundation; either
  6. version 2.1 of the License, or (at your option) any later version.
  7. The GNU C Library is distributed in the hope that it will be useful,
  8. but WITHOUT ANY WARRANTY; without even the implied warranty of
  9. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  10. Lesser General Public License for more details.
  11. You should have received a copy of the GNU Lesser General Public
  12. License along with the GNU C Library; if not, see
  13. <http://www.gnu.org/licenses/>. */
  14. #include <stdio.h>
  15. #include <string.h>
  16. #include "../misc/internals/tempname.h"
  17. static char tmpnam_buffer[L_tmpnam];
  18. /* Generate a unique filename in P_tmpdir.
  19. This function is *not* thread safe! */
  20. char *
  21. tmpnam (char *s)
  22. {
  23. /* By using two buffers we manage to be thread safe in the case
  24. where S != NULL. */
  25. char tmpbufmem[L_tmpnam];
  26. char *tmpbuf = s ?: tmpbufmem;
  27. /* In the following call we use the buffer pointed to by S if
  28. non-NULL although we don't know the size. But we limit the size
  29. to L_tmpnam characters in any case. */
  30. if (__builtin_expect (__path_search (tmpbuf, L_tmpnam, NULL, NULL, 0),
  31. 0))
  32. return NULL;
  33. if (__builtin_expect (__gen_tempname (tmpbuf, __GT_NOCREATE, 0, 0), 0))
  34. return NULL;
  35. if (s == NULL)
  36. return (char *) memcpy (tmpnam_buffer, tmpbuf, L_tmpnam);
  37. return s;
  38. }