libc-tsd.h 2.5 KB

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  1. /* libc-internal interface for thread-specific data. Stub or TLS version.
  2. Copyright (C) 1998-2019 Free Software Foundation, Inc.
  3. 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.
  8. The GNU C Library is distributed in the hope that it will be useful,
  9. but WITHOUT ANY WARRANTY; without even the implied warranty of
  10. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  11. Lesser General Public License for more details.
  12. You should have received a copy of the GNU Lesser General Public
  13. License along with the GNU C Library; if not, see
  14. <http://www.gnu.org/licenses/>. */
  15. #ifndef _GENERIC_LIBC_TSD_H
  16. #define _GENERIC_LIBC_TSD_H 1
  17. /* This file defines the following macros for accessing a small fixed
  18. set of thread-specific `void *' data used only internally by libc.
  19. __libc_tsd_define(CLASS, TYPE, KEY) -- Define or declare a datum with TYPE
  20. for KEY. CLASS can be `static' for
  21. keys used in only one source file,
  22. empty for global definitions, or
  23. `extern' for global declarations.
  24. __libc_tsd_address(TYPE, KEY) -- Return the `TYPE *' pointing to
  25. the current thread's datum for KEY.
  26. __libc_tsd_get(TYPE, KEY) -- Return the `TYPE' datum for KEY.
  27. __libc_tsd_set(TYPE, KEY, VALUE) -- Set the datum for KEY to VALUE.
  28. The set of available KEY's will usually be provided as an enum,
  29. and contains (at least):
  30. _LIBC_TSD_KEY_MALLOC
  31. _LIBC_TSD_KEY_DL_ERROR
  32. _LIBC_TSD_KEY_RPC_VARS
  33. All uses must be the literal _LIBC_TSD_* name in the __libc_tsd_* macros.
  34. Some implementations may not provide any enum at all and instead
  35. using string pasting in the macros. */
  36. #include <tls.h>
  37. /* When full support for __thread variables is available, this interface is
  38. just a trivial wrapper for it. Without TLS, this is the generic/stub
  39. implementation for wholly single-threaded systems.
  40. We don't define an enum for the possible key values, because the KEYs
  41. translate directly into variables by macro magic. */
  42. #define __libc_tsd_define(CLASS, TYPE, KEY) \
  43. CLASS __thread TYPE __libc_tsd_##KEY attribute_tls_model_ie;
  44. #define __libc_tsd_address(TYPE, KEY) (&__libc_tsd_##KEY)
  45. #define __libc_tsd_get(TYPE, KEY) (__libc_tsd_##KEY)
  46. #define __libc_tsd_set(TYPE, KEY, VALUE) (__libc_tsd_##KEY = (VALUE))
  47. #endif /* libc-tsd.h */