一直使用boost的scope_lock，今天想来看下boost thread库的各种功能，看到还有shared_lock / upgrade_lock。学习一下。
Mutex
Lock
总结
独占锁（写锁）
Lock_guard(不能与timed_mutex配合）
Unique_lock
boost::lock_guard<>和boost::unique_lock<>的区别
boost::mutex m;
void foo( )
{
boost::lock_guard<boost::mutex> lk( m );
process( data );
};
lock_guard只能像上面这样使用，而unique_lock允许设置超时，推迟锁定lock以及在对象销毁之前unlock。
{
boost::unique_lock<boost::mutex> lk( m );
process( data );
lk.unlock( );
// do other thing
};
读锁
Shared_lock
锁的升级
boost::shared_mutex _access;
void reader()
{
boost::shared_lock< boost::shared_mutex > lock(_access);
// do work here, without anyone having exclusive access
}
void conditional_writer()
{
boost::upgrade_lock< boost::shared_mutex > lock(_access);
// do work here, without anyone having exclusive access
if (something) {
boost::upgrade_to_unique_lock< boost::shared_mutex > uniqueLock(lock);
// do work here, but now you have exclusive access
}
// do more work here, without anyone having exclusive access
}
void unconditional_writer()
{
boost::unique_lock< boost::shared_mutex > lock(lock);
// do work here, with exclusive access
}
参考资料
http://www.boost.org/doc/libs/1_45_0/doc/html/thread/synchronization.html#thread.synchronization.locks
http://www.boost.org/doc/libs/1_45_0/doc/html/thread/synchronization.html#thread.synchronization.mutex_types.try_mutex
http://blog.csdn.net/hbhhww/article/details/7416170