BinarySemaphore.h
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#pragma once
#include "CappedSemaphore.h"
namespace baselib
{
BASELIB_CPP_INTERFACE
{
// In computer science, a semaphore is a variable or abstract data type used to control access to a common resource by multiple processes in a concurrent
// system such as a multitasking operating system. A semaphore is simply a variable. This variable is used to solve critical section problems and to achieve
// process synchronization in the multi processing environment. A trivial semaphore is a plain variable that is changed (for example, incremented or
// decremented, or toggled) depending on programmer-defined conditions.
//
// A useful way to think of a semaphore as used in the real-world system is as a record of how many units of a particular resource are available, coupled with
// operations to adjust that record safely (i.e. to avoid race conditions) as units are required or become free, and, if necessary, wait until a unit of the
// resource becomes available.
//
// "Semaphore (programming)", Wikipedia: The Free Encyclopedia
// https://en.wikipedia.org/w/index.php?title=Semaphore_(programming)&oldid=872408126
//
// For optimal performance, baselib::BinarySemaphore should be stored at a cache aligned memory location.
class BinarySemaphore : private CappedSemaphore
{
public:
// Creates a binary semaphore synchronization primitive.
// Binary means the semaphore can at any given time have at most one token available for consummation.
//
// This is just an API facade for CappedSemaphore(1)
//
// If there are not enough system resources to create a semaphore, process abort is triggered.
BinarySemaphore() : CappedSemaphore(1) {}
using CappedSemaphore::Acquire;
using CappedSemaphore::TryAcquire;
using CappedSemaphore::TryTimedAcquire;
// Submit token to the semaphore.
// If threads are waiting the token is consumed before this function return.
//
// When successful this function is guaranteed to emit a release barrier.
inline bool Release()
{
return CappedSemaphore::Release(1) == 1;
}
};
}
}