USemaphore Class Reference

#include <USemaphore.h>

Public Member Functions
	USemaphore (int initValue=0)
bool	acquire (int n=1, int ms=0)
int	acquireTry (int n)
int	release (int n=1)
int	value ()

Detailed Description

A semaphore class.

On an acquire() call, the calling thread is blocked if the USemaphore's value is <= 0. It is unblocked when release() is called. The function acquire() decreases by 1 (default) the semaphore's value and release() increases it by 1 (default).

Example:

USemaphore s;
s.acquire(); // Will wait until s.release() is called by another thread.

See also

UMutex

Definition at line 55 of file USemaphore.h.

Constructor & Destructor Documentation

USemaphore()

USemaphore::USemaphore ( int  initValue = 0 )

inline

The constructor. The semaphore waits on acquire() when its value is <= 0.

Parameters

n	number to initialize

Definition at line 62 of file USemaphore.h.

~USemaphore()

virtual USemaphore::~USemaphore ( )

inlinevirtual

Definition at line 76 of file USemaphore.h.

Member Function Documentation

acquire()

bool USemaphore::acquire ( int  n = 1, int  ms = 0  )

inline

Acquire the semaphore. If semaphore's value is <=0, the calling thread will wait until the count acquired is released.

See also

release()

Parameters

n	number to acquire
t	time to wait (ms), a value <=0 means infinite

Returns

true on success, false on error/timeout

Definition at line 108 of file USemaphore.h.

acquireTry()

int USemaphore::acquireTry ( int  n )

inline

Parameters

n	the number to acquire.

Definition at line 164 of file USemaphore.h.

release()

int USemaphore::release ( int  n = 1 )

inline

Release the semaphore, increasing its value by n and signaling waiting threads (which called acquire()).

Parameters

n	the number to release.

Returns

0 on success, ERANGE if the release would push the semaphore over SEM_VALUE_MAX (the count is then left unchanged). The Unix implementation cannot fail and always returns 0.

Definition at line 197 of file USemaphore.h.

value()

int USemaphore::value ( )

inline

Get the USempahore's value.

Returns

the semaphore's value

Definition at line 221 of file USemaphore.h.

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The documentation for this class was generated from the following file:

• utilite/include/rtabmap/utilite/USemaphore.h