micxx::Semaphore Class Reference

The Semaphore implements a counting semaphore with the ability of claiming or returning more than one unit from the semaphore and with support for timeout detection. More...

#include <micxx.hxx>

Inherits micxx::Condition.

List of all members.

Public Member Functions
	Semaphore (int initialValue=1)
	Create a new Semaphore with initialValue.
virtual unsigned	getValue () const
	The current counter value.
virtual bool	acquire (int avalue=1, unsigned long timeoutMillis=0)
	Try to acquire the unit avalue of the counter value within timeoutMillis.
virtual void	release (int avalue=1)
	Release the unit avalue of the counter value.

---

Detailed Description

The Semaphore implements a counting semaphore with the ability of claiming or returning more than one unit from the semaphore and with support for timeout detection.

If s is the internal kept counter value, the Semaphore is implemented in the following way:

 Semaphore::acquire(int howmany[, unsigned long timeout])
 {
     wait until s >= 0;
     s := s - howmany; // must be atomic operation
     wait until s >= 0;
 }

 Semaphore::release(int howmany)
 {
     s := s+howmany;   // must be atomic
 }

Author:

Norbert Klose

Date:

December, 2006

---

Constructor & Destructor Documentation

micxx::Semaphore::Semaphore

(

int

initialValue = 1

)

Create a new Semaphore with initialValue.

Parameters:

initialValue

The initial counter value. This is the maximum value which could be acquired without blocking the current calling thread.

---

Member Function Documentation

virtual bool micxx::Semaphore::acquire	(	int	avalue = 1,
		unsigned long	timeoutMillis = 0
	)		[virtual]

Try to acquire the unit avalue of the counter value within timeoutMillis.

Parameters:

avalue	The unit of the counter value to be acquired at once.
timeoutMillis	If greater 0, wait at most timeoutMillis until the call returns (regardless if the lock has successfully been acquired or not).

Returns:

true, if the lock has been successfully acquired,
false, otherwise.

virtual unsigned micxx::Semaphore::getValue

(

)

const [virtual]

The current counter value.

This is the maximum value which could be acquired without blocking the current calling thread.

virtual void micxx::Semaphore::release

(

int

avalue = 1

)

[virtual]

Release the unit avalue of the counter value.

---

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

• include/micxx/Semaphore.hxx