Semaphore Class Reference

This is your classic semaphore, used to implement synchronization between tasks. More...

#include <semaphore.h>

Collaboration diagram for Semaphore:

[legend]List of all members.

Public Member Functions
void	init (unsigned start_value=1)
bool	acquire (unsigned timeout=0)
bool	try_acquire ()
bool	release ()
void	remove_task (Task *task)
void	print ()
Protected Attributes
List< Task >	waiting_tasks
unsigned	value

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Detailed Description

This is your classic semaphore, used to implement synchronization between tasks.

Acquiring a semaphore that is already acquired causes the call to block until the semaphore becomes released.

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Member Function Documentation

bool Semaphore::acquire (  unsigned  timeout = 0  )

Lock this semaphore. If it's already locked, first block until it becomes unlocked and return true. An optional timeout in milliseconds can be given. If a timeout occurs before the lock is successful, return false.

void Semaphore::init (  unsigned  start_value = 1  )

Initialize this semaphore's default value. Setting a default value higher than 1 means that the semaphore can be acquire()d multiple times before subsequent acquire() invocations block. Setting a default value of 0 means that every acquire() call to this semaphore will block.

void Semaphore::print (   )

Print basic information about this semaphore.

bool Semaphore::release (   )

Unlock this semaphore and wake up one thread that is waiting to acquire it. Return true if there was a thread to wake up.

void Semaphore::remove_task (  Task *  task  )

Remove a task from this semaphore's waiting task list.

bool Semaphore::try_acquire (   )

Attempt to lock this semaphore without blocking. Return true on success or false if it is already locked.

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Member Data Documentation

unsigned Semaphore::value [protected]

current value of this semaphore

List<Task> Semaphore::waiting_tasks [protected]

tasks waiting for this semaphore

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

• semaphore.h
• semaphore.cc

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Torsion Operating System, Copyright (C) 2000-2004 Dan Helfman