1 /* Basic platform-independent macro definitions for mutexes,

     2    thread-specific data and parameters for malloc.

     3    Copyright (C) 2003 Free Software Foundation, Inc.

     4    This file is part of the GNU C Library.

     5 

     6    The GNU C Library is free software; you can redistribute it and/or

     7    modify it under the terms of the GNU Lesser General Public

     8    License as published by the Free Software Foundation; either

     9    version 2.1 of the License, or (at your option) any later version.

    10 

    11    The GNU C Library is distributed in the hope that it will be useful,

    12    but WITHOUT ANY WARRANTY; without even the implied warranty of

    13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

    14    Lesser General Public License for more details.

    15 

    16    You should have received a copy of the GNU Lesser General Public

    17    License along with the GNU C Library; if not, write to the Free

    18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA

    19    02111-1307 USA.  */

    20 

    21 #ifndef _GENERIC_MALLOC_MACHINE_H

    22 #define _GENERIC_MALLOC_MACHINE_H

    23 

    24 #include <atomic.h>

    25 

    26 #ifndef mutex_init /* No threads, provide dummy macros */

    27 

    28 # define NO_THREADS

    29 

    30 /* The mutex functions used to do absolutely nothing, i.e. lock,

    31    trylock and unlock would always just return 0.  However, even

    32    without any concurrently active threads, a mutex can be used

    33    legitimately as an `in use' flag.  To make the code that is

    34    protected by a mutex async-signal safe, these macros would have to

    35    be based on atomic test-and-set operations, for example. */

    36 typedef int mutex_t;

    37 

    38 # define mutex_init(m)              (*(m) = 0)

    39 # define mutex_lock(m)              ((*(m) = 1), 0)

    40 # define mutex_trylock(m)           (*(m) ? 1 : ((*(m) = 1), 0))

    41 # define mutex_unlock(m)            (*(m) = 0)

    42 

    43 typedef void *tsd_key_t;

    44 # define tsd_key_create(key, destr) do {} while(0)

    45 # define tsd_setspecific(key, data) ((key) = (data))

    46 # define tsd_getspecific(key, vptr) (vptr = (key))

    47 

    48 # define thread_atfork(prepare, parent, child) do {} while(0)

    49 

    50 #endif /* !defined mutex_init */

    51 

    52 #ifndef atomic_full_barrier

    53 # define atomic_full_barrier() __asm ("" ::: "memory")

    54 #endif

    55 

    56 #ifndef atomic_read_barrier

    57 # define atomic_read_barrier() atomic_full_barrier ()

    58 #endif

    59 

    60 #ifndef atomic_write_barrier

    61 # define atomic_write_barrier() atomic_full_barrier ()

    62 #endif

    63 

    64 #ifndef DEFAULT_TOP_PAD

    65 # define DEFAULT_TOP_PAD 131072

    66 #endif

    67 

    68 #endif /* !defined(_GENERIC_MALLOC_MACHINE_H) */