1 /* libc-internal interface for thread-specific data. Stub or TLS version. 2 Copyright (C) 1998-2022 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, see 17 <https://www.gnu.org/licenses/>. */ 18 19 #ifndef _GENERIC_LIBC_TSD_H 20 #define _GENERIC_LIBC_TSD_H 1 21 22 /* This file defines the following macros for accessing a small fixed 23 set of thread-specific `void *' data used only internally by libc. 24 25 __libc_tsd_define(CLASS, TYPE, KEY) -- Define or declare a datum with TYPE 26 for KEY. CLASS can be `static' for 27 keys used in only one source file, 28 empty for global definitions, or 29 `extern' for global declarations. 30 __libc_tsd_address(TYPE, KEY) -- Return the `TYPE *' pointing to 31 the current thread's datum for KEY. 32 __libc_tsd_get(TYPE, KEY) -- Return the `TYPE' datum for KEY. 33 __libc_tsd_set(TYPE, KEY, VALUE) -- Set the datum for KEY to VALUE. 34 35 The set of available KEY's will usually be provided as an enum, 36 and contains (at least): 37 _LIBC_TSD_KEY_MALLOC 38 _LIBC_TSD_KEY_DL_ERROR 39 _LIBC_TSD_KEY_RPC_VARS 40 All uses must be the literal _LIBC_TSD_* name in the __libc_tsd_* macros. 41 Some implementations may not provide any enum at all and instead 42 using string pasting in the macros. */ 43 44 #include <tls.h> 45 46 /* When full support for __thread variables is available, this interface is 47 just a trivial wrapper for it. Without TLS, this is the generic/stub 48 implementation for wholly single-threaded systems. 49 50 We don't define an enum for the possible key values, because the KEYs 51 translate directly into variables by macro magic. */ 52 53 #define __libc_tsd_define(CLASS, TYPE, KEY) \ 54 CLASS __thread TYPE __libc_tsd_##KEY attribute_tls_model_ie; 55 56 #define __libc_tsd_address(TYPE, KEY) (&__libc_tsd_##KEY) 57 #define __libc_tsd_get(TYPE, KEY) (__libc_tsd_##KEY) 58 #define __libc_tsd_set(TYPE, KEY, VALUE) (__libc_tsd_##KEY = (VALUE)) 59 60 #endif /* libc-tsd.h */ 61