mrpt::synch::CSemaphore Class Reference

Detailed Description

A semaphore for inter-thread synchronization.

The state of a semaphore object is signaled when its count is greater than zero, and nonsignaled when its count is equal to zero. The initialCount parameter specifies the initial count. Each time a waiting thread is released because of the semaphore's signaled state, the count of the semaphore is decreased by one. Use the release function to increment a semaphore's count by a specified amount. The count can never be less than zero or greater than the value specified in the maxCount parameter.

Definition at line 31 of file CSemaphore.h.

#include <mrpt/synch/CSemaphore.h>

Public Member Functions
	CSemaphore (unsigned int initialCount, unsigned int maxCount)
	Creates a semaphore. More...
	CSemaphore (const CSemaphore &o)
bool	waitForSignal (unsigned int timeout_ms=0)
	Blocks until the count of the semaphore to be non-zero. More...
void	release (unsigned int increaseCount=1)
	Increments the count of the semaphore by a given amount. More...

Protected Attributes
std::mutex	m_mutex
std::condition_variable	m_condition
unsigned long	m_count { 0 }

Constructor & Destructor Documentation

CSemaphore() [1/2]

CSemaphore::CSemaphore	(	unsigned int	initialCount,
		unsigned int	maxCount
	)

Creates a semaphore.

Definition at line 17 of file CSemaphore.cpp.

References m_count.

CSemaphore() [2/2]

mrpt::synch::CSemaphore::CSemaphore ( const CSemaphore &  o )

inline

Definition at line 43 of file CSemaphore.h.

Member Function Documentation

release()

void CSemaphore::release

(

unsigned int

increaseCount = 1

)

Increments the count of the semaphore by a given amount.

Definition at line 41 of file CSemaphore.cpp.

References m_condition, m_count, m_mutex, MRPT_END, and MRPT_START.

Referenced by mrpt::detectors::CFaceDetection::detectObjects_Impl(), mrpt::gui::CWindowDialog::OnClose(), mrpt::gui::C3DWindowDialog::OnClose(), CDisplayWindow_WXAPP::OnInit(), mrpt::gui::WxSubsystem::CWXMainFrame::OnTimerProcessRequests(), mrpt::hwdrivers::CNTRIPClient::private_ntrip_thread(), sem_thread_example(), mrpt::detectors::CFaceDetection::thread_checkIfDiagonalSurface(), mrpt::detectors::CFaceDetection::thread_checkIfFacePlaneCov(), mrpt::detectors::CFaceDetection::thread_checkIfFaceRegions(), mrpt::gui::WxSubsystem::wxMainThread(), and mrpt::detectors::CFaceDetection::~CFaceDetection().

waitForSignal()

bool CSemaphore::waitForSignal

(

unsigned int

timeout_ms = 0

)

Blocks until the count of the semaphore to be non-zero.

Parameters

timeout_ms

The timeout in milliseconds, or set to zero to wait indefinidely.

Returns

true if the semaphore has been signaled, false on timeout or any other error.

Definition at line 24 of file CSemaphore.cpp.

References m_condition, m_count, m_mutex, MRPT_END, and MRPT_START.

Referenced by mrpt::hwdrivers::CNTRIPClient::close(), mrpt::gui::WxSubsystem::createOneInstanceMainThread(), mrpt::detectors::CFaceDetection::detectObjects_Impl(), mrpt::hwdrivers::CNTRIPClient::open(), mrpt::hwdrivers::prepareVideoSourceFromUserSelection(), sem_thread_example(), mrpt::detectors::CFaceDetection::thread_checkIfDiagonalSurface(), mrpt::detectors::CFaceDetection::thread_checkIfFacePlaneCov(), and mrpt::detectors::CFaceDetection::thread_checkIfFaceRegions().

Member Data Documentation

m_condition

std::condition_variable mrpt::synch::CSemaphore::m_condition

protected

Definition at line 35 of file CSemaphore.h.

Referenced by release(), and waitForSignal().

m_count

unsigned long mrpt::synch::CSemaphore::m_count { 0 }

protected

Definition at line 36 of file CSemaphore.h.

Referenced by CSemaphore(), release(), and waitForSignal().

m_mutex

std::mutex mrpt::synch::CSemaphore::m_mutex

protected

Definition at line 34 of file CSemaphore.h.

Referenced by release(), and waitForSignal().