libvirt/src/util/threads.h
Eric Blake 99de59900a threads: add one-time initialization support
mingw lacks the counterpart to PTHREAD_MUTEX_INITIALIZER, so the
best we can do is portably expose once-only runtime initialization.

* src/util/threads.h (virOnceControlPtr): New opaque type.
(virOnceFunc): New callback type.
(virOnce): New prototype.
* src/util/threads-pthread.h (virOnceControl): Declare.
(VIR_ONCE_CONTROL_INITIALIZER): Define.
* src/util/threads-win32.h (virOnceControl)
(VIR_ONCE_CONTROL_INITIALIZER): Likewise.
* src/util/threads-pthread.c (virOnce): Implement in pthreads.
* src/util/threads-win32.c (virOnce): Implement in WIN32.
* src/libvirt_private.syms: Export it.
2011-04-25 08:53:09 -06:00

112 lines
3.6 KiB
C

/*
* threads.h: basic thread synchronization primitives
*
* Copyright (C) 2009-2011 Red Hat, Inc.
*
* This 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.
*
* This 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 this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#ifndef __THREADS_H_
# define __THREADS_H_
# include "internal.h"
typedef struct virMutex virMutex;
typedef virMutex *virMutexPtr;
typedef struct virCond virCond;
typedef virCond *virCondPtr;
typedef struct virThreadLocal virThreadLocal;
typedef virThreadLocal *virThreadLocalPtr;
typedef struct virThread virThread;
typedef virThread *virThreadPtr;
typedef struct virOnceControl virOnceControl;
typedef virOnceControl *virOnceControlPtr;
typedef void (*virOnceFunc)(void);
int virThreadInitialize(void) ATTRIBUTE_RETURN_CHECK;
void virThreadOnExit(void);
typedef void (*virThreadFunc)(void *opaque);
int virThreadCreate(virThreadPtr thread,
bool joinable,
virThreadFunc func,
void *opaque) ATTRIBUTE_RETURN_CHECK;
void virThreadSelf(virThreadPtr thread);
bool virThreadIsSelf(virThreadPtr thread);
void virThreadJoin(virThreadPtr thread);
/* These next two functions are for debugging only, since they are not
* guaranteed to give unique values for distinct threads on all
* architectures, nor are the two functions guaranteed to give the same
* value for the same thread. */
int virThreadSelfID(void);
int virThreadID(virThreadPtr thread);
/* Static initialization of mutexes is not possible, so we instead
* provide for guaranteed one-time initialization via a callback
* function. Usage:
* static virOnceControl once = VIR_ONCE_CONTROL_INITIALIZER;
* static void initializer(void) { ... }
* void myfunc()
* {
* if (virOnce(&once, initializer) < 0)
* goto error;
* ...now guaranteed that initializer has completed exactly once
* }
*/
int virOnce(virOnceControlPtr once, virOnceFunc init)
ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_RETURN_CHECK;
int virMutexInit(virMutexPtr m) ATTRIBUTE_RETURN_CHECK;
int virMutexInitRecursive(virMutexPtr m) ATTRIBUTE_RETURN_CHECK;
void virMutexDestroy(virMutexPtr m);
void virMutexLock(virMutexPtr m);
void virMutexUnlock(virMutexPtr m);
int virCondInit(virCondPtr c) ATTRIBUTE_RETURN_CHECK;
int virCondDestroy(virCondPtr c) ATTRIBUTE_RETURN_CHECK;
int virCondWait(virCondPtr c, virMutexPtr m) ATTRIBUTE_RETURN_CHECK;
int virCondWaitUntil(virCondPtr c, virMutexPtr m, unsigned long long whenms) ATTRIBUTE_RETURN_CHECK;
void virCondSignal(virCondPtr c);
void virCondBroadcast(virCondPtr c);
typedef void (*virThreadLocalCleanup)(void *);
int virThreadLocalInit(virThreadLocalPtr l,
virThreadLocalCleanup c) ATTRIBUTE_RETURN_CHECK;
void *virThreadLocalGet(virThreadLocalPtr l);
void virThreadLocalSet(virThreadLocalPtr l, void*);
# ifdef WIN32
# include "threads-win32.h"
# elif defined HAVE_PTHREAD_MUTEXATTR_INIT
# include "threads-pthread.h"
# else
# error "Either pthreads or Win32 threads are required"
# endif
#endif