PLearn::ResourceSemaphore Class Reference

#include <Semaphores.h>

Collaboration diagram for PLearn::ResourceSemaphore:

[legend]List of all members.

Public Member Functions
	ResourceSemaphore (int nb_semaphores=1)
	construct given number of semaphores for controlling so many exclusive resources.
	ResourceSemaphore (SemId semid)
	access an existing semaphore
void	lock (int resource=0)
void	unlock (int resource=0)
	Release a lock on a resource.
bool	locked (int resource=0)
	to check without waiting wether a resource is locked.
void	clearAnyLock ()
	make sure we are back in unlocked mode: clear locks of all resources
void	clearAnyLock (int resource)
	make sure we are back in unlocked mode: clear lock for given resource
	~ResourceSemaphore ()
	release the semaphore upon destruction of object
Protected Attributes
SemId	id
	semaphore id provided by the operating system at construction
bool	owner
	true if this process is the owner of the semaphore, i.e
int	n_semaphores
	there can be several semaphores in the same object

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Constructor & Destructor Documentation

PLearn::ResourceSemaphore::ResourceSemaphore (  int  nb_semaphores = 1  )

construct given number of semaphores for controlling so many exclusive resources. Definition at line 49 of file Semaphores.cc. References clearAnyLock(), PLearn::endl(), n_semaphores, and PLERROR.

PLearn::ResourceSemaphore::ResourceSemaphore (  SemId  semid  )

access an existing semaphore Definition at line 62 of file Semaphores.cc. References n_semaphores, and PLERROR.

PLearn::ResourceSemaphore::~ResourceSemaphore (   )

release the semaphore upon destruction of object Definition at line 124 of file Semaphores.cc. References PLearn::endl(), owner, PLERROR, and PLearn::semun::val.

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Member Function Documentation

void PLearn::ResourceSemaphore::clearAnyLock (  int  resource  )

make sure we are back in unlocked mode: clear lock for given resource Definition at line 114 of file Semaphores.cc. References PLERROR, and PLearn::semun::val.

void PLearn::ResourceSemaphore::clearAnyLock (   )

make sure we are back in unlocked mode: clear locks of all resources Definition at line 108 of file Semaphores.cc. References n_semaphores. Referenced by ResourceSemaphore().

void PLearn::ResourceSemaphore::lock (  int  resource = 0  )

Wait for a resource to be freed and then take control of it. This is done by waiting for the resource semaphore's to become 1 and then decrementing its value to 0 (thus taking the lock). Definition at line 74 of file Semaphores.cc. References PLERROR.

bool PLearn::ResourceSemaphore::locked (  int  resource = 0  )

to check without waiting wether a resource is locked. Definition at line 101 of file Semaphores.cc. References PLearn::semun::val. Referenced by unlock().

void PLearn::ResourceSemaphore::unlock (  int  resource = 0  )

Release a lock on a resource. This is done by incrementing the resource's semaphore. No waiting. Definition at line 86 of file Semaphores.cc. References locked(), and PLERROR.

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Member Data Documentation

SemId PLearn::ResourceSemaphore::id [protected]

semaphore id provided by the operating system at construction Definition at line 96 of file Semaphores.h.

int PLearn::ResourceSemaphore::n_semaphores [protected]

there can be several semaphores in the same object Definition at line 99 of file Semaphores.h. Referenced by clearAnyLock(), and ResourceSemaphore().

bool PLearn::ResourceSemaphore::owner [protected]

true if this process is the owner of the semaphore, i.e the semaphore will be released with this object is deleted Definition at line 97 of file Semaphores.h. Referenced by ~ResourceSemaphore().

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

• Semaphores.h
• Semaphores.cc

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