Question

my case is one thread read and want to
decide if needed to change the value or not?

some thing like below

void set(bool status)
{ 
    if(status == m_status)
         return;
     monitor.lock();
     m_status = status;

}

if this possible?

Answer 1

Using a synchronization object for boolean state is overkill.

On Windows you can use Interlocked Variable Access.

For cross platform solution .. see Boost Atomic

std::atomic from C++11 is also a solution