Semaphore Class Reference

Semaphore used for synchronization of threads. More...

#include <sync/semaphore.h>

Inheritance diagram for Semaphore:

Collaboration diagram for Semaphore:

Public Member Functions
	Semaphore (unsigned c=0)
	Constructor; initialized the counter with provided value c
void	p ()
	Wait for access to the critical area.
void	v ()
	Leave the critical area.
Public Member Functions inherited from Waitingroom
	Waitingroom ()
	Constructor.
virtual	~Waitingroom ()
	Destructor.
virtual void	remove (Thread *customer)
	Remove a given thread prematurely from the Waitingroom.
Public Member Functions inherited from Queue< T, ContainerType >
	Queue ()
	Default constructor; initialized the queue as empty.
void	enqueue (T *item)
	Enqueues the provided item at the end of the queue.
T *	dequeue ()
	Removes the first element in the queue and returns it.
Iterator	begin ()
Iterator	end ()
T *	remove (T *item, bool(*cmp)(T *, T *)=[](T *a, T *b) {return a==b;})
	Removes and returns a single element from the queue.
void	insertFirst (T *item)
	Adds item to the beginning of the queue.
void	insertAfter (T *old_item, T *new_item)
	Inserts the element new_item directly after old_item.
T *	first ()
	Returns the first element in the queue without removing it.
T *	next (T *o)
	Returns the next element in the queue for a given element.

Private Member Functions
	Semaphore (const Semaphore &)=delete
Semaphore &	operator= (const Semaphore &)=delete

Private Attributes
unsigned	counter

Detailed Description

Semaphore used for synchronization of threads.

The class Semaphore implements the concept of counting semaphores. The waiting list is provided by the base class Waitingroom.

Constructor & Destructor Documentation

Semaphore() [1/2]

Semaphore::Semaphore ( const Semaphore &  )

privatedelete

Semaphore() [2/2]

Semaphore::Semaphore ( unsigned  c = 0 )

inlineexplicit

Constructor; initialized the counter with provided value c

Parameters

c	Initial counter value

Member Function Documentation

operator=()

Semaphore & Semaphore::operator= ( const Semaphore &  )

privatedelete

p()

void Semaphore::p

(

)

Wait for access to the critical area.

Enter/Wait operation: If the counter is greater than 0, then it is decremented by one. Otherwise the calling thread will be enqueued into the Waitingroom and marked as blocked.

v()

void Semaphore::v

(

)

Leave the critical area.

Leave operation: If there are threads in the Waitingroom, wake the first one; otherwise increment the counter by one.

Member Data Documentation

counter

unsigned Semaphore::counter

private

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

• sync/semaphore.h
• sync/semaphore.cc