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→What is a Lock?
void GameOfThronesClass::GuardTheWall(){
//Protect until Unlock() is called. Only 1 thread may do this below at a time. It is //"locked"
NightsWatch.Lock();
}
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Note that there can be problems with locks. If a thread is locked but it is never unlocked, any other threads will be forced to wait which may cause performance issues. Another problem is called "Dead Locking" where each thread may be waiting for another to unlock (and vice versa) and the program is forced to wait and wait .
===Parallelism Problems in STL===
