urcu.h

   1 #ifndef _URCU_H
   2 #define _URCU_H
   3
   4 /*
   5  * urcu.h
   6  *
   7  * Userspace RCU header
   8  *
   9  * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
  10  * Copyright (c) 2009 Paul E. McKenney, IBM Corporation.
  11  *
  12  * LGPL-compatible code should include this header with :
  13  *
  14  * #define _LGPL_SOURCE
  15  * #include <urcu.h>
  16  *
  17  * This library is free software; you can redistribute it and/or
  18  * modify it under the terms of the GNU Lesser General Public
  19  * License as published by the Free Software Foundation; either
  20  * version 2.1 of the License, or (at your option) any later version.
  21  *
  22  * This library is distributed in the hope that it will be useful,
  23  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  24  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  25  * Lesser General Public License for more details.
  26  *
  27  * You should have received a copy of the GNU Lesser General Public
  28  * License along with this library; if not, write to the Free Software
  29  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  30  *
  31  * IBM's contributions to this file may be relicensed under LGPLv2 or later.
  32  */
  33
  34 #include <stdlib.h>
  35 #include <pthread.h>
  36
  37 /*
  38  * See urcu-pointer.h and urcu-pointer-static.h for pointer publication headers.
  39  */
  40 #include <urcu-pointer.h>
  41
  42 /*
  43  * Important !
  44  *
  45  * Each thread containing read-side critical sections must be registered
  46  * with rcu_register_thread() before calling rcu_read_lock().
  47  * rcu_unregister_thread() should be called before the thread exits.
  48  */
  49
  50 #ifdef _LGPL_SOURCE
  51
  52 #include <urcu-static.h>
  53
  54 /*
  55  * Mappings for static use of the userspace RCU library.
  56  * Should only be used in LGPL-compatible code.
  57  */
  58
  59 /*
  60  * rcu_read_lock()
  61  * rcu_read_unlock()
  62  *
  63  * Mark the beginning and end of a read-side critical section.
  64  * DON'T FORGET TO USE RCU_REGISTER/UNREGISTER_THREAD() FOR EACH THREAD WITH
  65  * READ-SIDE CRITICAL SECTION.
  66  */
  67 #define rcu_read_lock()         _rcu_read_lock()
  68 #define rcu_read_unlock()       _rcu_read_unlock()
  69
  70 #else /* !_LGPL_SOURCE */
  71
  72 /*
  73  * library wrappers to be used by non-LGPL compatible source code.
  74  * See LGPL-only urcu-pointer-static.h for documentation.
  75  */
  76
  77 extern void rcu_read_lock(void);
  78 extern void rcu_read_unlock(void);
  79
  80 #endif /* !_LGPL_SOURCE */
  81
  82 extern void synchronize_rcu(void);
  83
  84 /*
  85  * Reader thread registration.
  86  */
  87 extern void rcu_register_thread(void);
  88 extern void rcu_unregister_thread(void);
  89
  90 /*
  91  * Explicit urcu initialization, for "early" use within library constructors.
  92  */
  93 extern void urcu_init(void);
  94
  95 #endif /* _URCU_H */