Synchronization Primitives for Multi-Threading

To support multi-threading, some parts of STXXL use synchronization primitives to ensure correct results. The primitives are based either on pthreads or on Boost classes.

Mutexes

For simple mutual exclusion contexts, stxxl::mutex objects should be used together with scoped locks:

class Something
{
 stxxl::mutex m_mtx;
 void critical_function()
 {
 stxxl::scoped_mutex_lock lock(m_mtx);
 // do something requiring locking
 }
};

Semaphores

Additionally stxxl::semaphore is available if counting is required.

Further Primitives: State and OnOff-Switch

stxxl::state is a synchronized state switching mechanism?

stxxl::onoff_switch is a two state semaphore thing?