glibc/bits/libc-tsd.h
2012-02-09 23:18:22 +00:00

61 lines
2.6 KiB
C

/* libc-internal interface for thread-specific data. Stub or TLS version.
Copyright (C) 1998,2001,2002,2008,2011 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#ifndef _GENERIC_BITS_LIBC_TSD_H
#define _GENERIC_BITS_LIBC_TSD_H 1
/* This file defines the following macros for accessing a small fixed
set of thread-specific `void *' data used only internally by libc.
__libc_tsd_define(CLASS, TYPE, KEY) -- Define or declare a datum with TYPE
for KEY. CLASS can be `static' for
keys used in only one source file,
empty for global definitions, or
`extern' for global declarations.
__libc_tsd_address(TYPE, KEY) -- Return the `TYPE *' pointing to
the current thread's datum for KEY.
__libc_tsd_get(TYPE, KEY) -- Return the `TYPE' datum for KEY.
__libc_tsd_set(TYPE, KEY, VALUE) -- Set the datum for KEY to VALUE.
The set of available KEY's will usually be provided as an enum,
and contains (at least):
_LIBC_TSD_KEY_MALLOC
_LIBC_TSD_KEY_DL_ERROR
_LIBC_TSD_KEY_RPC_VARS
All uses must be the literal _LIBC_TSD_* name in the __libc_tsd_* macros.
Some implementations may not provide any enum at all and instead
using string pasting in the macros. */
#include <tls.h>
/* When full support for __thread variables is available, this interface is
just a trivial wrapper for it. Without TLS, this is the generic/stub
implementation for wholly single-threaded systems.
We don't define an enum for the possible key values, because the KEYs
translate directly into variables by macro magic. */
#define __libc_tsd_define(CLASS, TYPE, KEY) \
CLASS __thread TYPE __libc_tsd_##KEY attribute_tls_model_ie;
#define __libc_tsd_address(TYPE, KEY) (&__libc_tsd_##KEY)
#define __libc_tsd_get(TYPE, KEY) (__libc_tsd_##KEY)
#define __libc_tsd_set(TYPE, KEY, VALUE) (__libc_tsd_##KEY = (VALUE))
#endif /* bits/libc-tsd.h */