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ZThreads
A platform-independent, multi-threading and synchronization library for C++
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CountingSemaphore Class Reference

#include <CountingSemaphore.h>

Inheritance diagram for CountingSemaphore:

Lockable NonCopyable List of all members.

Public Member Functions

 CountingSemaphore (int initialCount=0)
virtual ~CountingSemaphore ()
 Destroy the CountingSemaphore.
void wait ()
bool tryWait (unsigned long timeout)
void post ()
virtual int count ()
virtual bool tryAcquire (unsigned long timeout)
virtual void acquire ()
virtual void release ()

Detailed Description

Author:
Eric Crahen <http://www.code-foo.com>
Date:
<2003-07-16T15:26:18-0400>
Version:
2.2.1
A CountingSemaphore is an owner-less Lockable object.

It differs from a normal Semaphore in that there is no upper bound on the count and it will not throw an exception because a maximum value has been exceeded.

See also:
Semaphore
Threads blocked on a CountingSemaphore are resumed in FIFO order.

Constructor & Destructor Documentation

CountingSemaphore (  int  initialCount = 0  ) 
 

Create a new CountingSemaphore.

Parameters:
count - initial count

Member Function Documentation

virtual void acquire (   )  [virtual]
 

Decrement the count, blocking that calling thread if the count becomes 0 or less than 0. The calling thread will remain blocked until the count is raised above 0 or if an exception is thrown.

Exceptions:
Interrupted_Exception thrown when the calling thread is interrupted. A thread may be interrupted at any time, prematurely ending any wait.
See also:
Lockable::acquire()

Implements Lockable.

virtual int count (   )  [virtual]
 

Get the current count of the semaphore.

This value may change immediately after this function returns to the calling thread.

Returns:
int count

void post (   ) 
 

Provided to reflect the traditional Semaphore semantics

See also:
release()

virtual void release (   )  [virtual]
 

Increment the count, unblocking one thread if count is positive.

See also:
Lockable::release()

Implements Lockable.

virtual bool tryAcquire (  unsigned long  timeout  )  [virtual]
 

Decrement the count, blocking that calling thread if the count becomes 0 or less than 0. The calling thread will remain blocked until the count is raised above 0, an exception is thrown or the given amount of time expires.

Parameters:
timeout maximum amount of time (milliseconds) this method could block
Returns:
  • true if the Semaphore was acquired before timeout milliseconds elapse.
  • false otherwise.
Exceptions:
Interrupted_Exception thrown when the calling thread is interrupted. A thread may be interrupted at any time, prematurely ending any wait.
See also:
Lockable::tryAcquire(unsigned long timeout)

Implements Lockable.

bool tryWait (  unsigned long  timeout  ) 
 

Provided to reflect the traditional Semaphore semantics

See also:
tryAcquire(unsigned long timeout)

void wait (   ) 
 

Provided to reflect the traditional Semaphore semantics

See also:
acquire()
The documentation for this class was generated from the following file:
ZThreads is Copyright © 2000-2005 by Eric Crahen, see the license for details.