在if语句评估中提升scoped_lock对象

Question

The following code compiles

scoped_lock<named_mutex> lock(some_mutex);
if (!lock) { // What does this means, which function is called
}

Since lock is an object what happens inthe if (!lock) . Does any overloaded function gets called.

Answer 1

operator unspecified_bool_type() const; , which returns owns() , will be called

http://live.boost.org/doc/libs/release/doc/html/boost/interprocess/scoped_lock.html