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[glibc/history.git] / bits / libc-tsd.h
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1 /* libc-internal interface for thread-specific data. Stub or TLS version.
2 Copyright (C) 1998,2001,2002,2008 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
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.
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.
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. */
20 #ifndef _GENERIC_BITS_LIBC_TSD_H
21 #define _GENERIC_BITS_LIBC_TSD_H 1
23 /* This file defines the following macros for accessing a small fixed
24 set of thread-specific `void *' data used only internally by libc.
26 __libc_tsd_define(CLASS, TYPE, KEY) -- Define or declare a datum with TYPE
27 for KEY. CLASS can be `static' for
28 keys used in only one source file,
29 empty for global definitions, or
30 `extern' for global declarations.
31 __libc_tsd_address(TYPE, KEY) -- Return the `TYPE *' pointing to
32 the current thread's datum for KEY.
33 __libc_tsd_get(TYPE, KEY) -- Return the `TYPE' datum for KEY.
34 __libc_tsd_set(TYPE, KEY, VALUE) -- Set the datum for KEY to VALUE.
36 The set of available KEY's will usually be provided as an enum,
37 and contains (at least):
38 _LIBC_TSD_KEY_MALLOC
39 _LIBC_TSD_KEY_DL_ERROR
40 _LIBC_TSD_KEY_RPC_VARS
41 All uses must be the literal _LIBC_TSD_* name in the __libc_tsd_* macros.
42 Some implementations may not provide any enum at all and instead
43 using string pasting in the macros. */
45 #include <tls.h>
47 /* When full support for __thread variables is available, this interface is
48 just a trivial wrapper for it. Without TLS, this is the generic/stub
49 implementation for wholly single-threaded systems.
51 We don't define an enum for the possible key values, because the KEYs
52 translate directly into variables by macro magic. */
54 #if USE___THREAD
55 # define __libc_tsd_define(CLASS, TYPE, KEY) \
56 CLASS __thread TYPE __libc_tsd_##KEY attribute_tls_model_ie;
58 # define __libc_tsd_address(TYPE, KEY) (&__libc_tsd_##KEY)
59 # define __libc_tsd_get(TYPE, KEY) (__libc_tsd_##KEY)
60 # define __libc_tsd_set(TYPE, KEY, VALUE) (__libc_tsd_##KEY = (VALUE))
61 #else
62 # define __libc_tsd_define(CLASS, TYPE, KEY) \
63 CLASS TYPE __libc_tsd_##KEY##_data;
65 # define __libc_tsd_address(TYPE, KEY) (&__libc_tsd_##KEY##_data)
66 # define __libc_tsd_get(TYPE, KEY) (__libc_tsd_##KEY##_data)
67 # define __libc_tsd_set(TYPE, KEY, VALUE) (__libc_tsd_##KEY##_data = (VALUE))
68 #endif
70 #endif /* bits/libc-tsd.h */