Public Member Functions | Private Attributes | List of all members
RTT::os::Semaphore Class Reference

#include <Semaphore.hpp>

Public Member Functions

 Semaphore (int count)
 
void signal ()
 
bool trywait ()
 
int value ()
 
void wait ()
 
 ~Semaphore ()
 

Private Attributes

rt_sem_t sem
 

Detailed Description

An object oriented wrapper around a counting semaphore. It works like a traffic light on which a thread can wait() until the sempahore's value becomes positive, otherwise it blocks. Another thread then needs to signal() the semaphore. One thread which is waiting will then be awakened, if none is waiting, the first thread calling wait() will continue directly (and decrease the value by 1).

Warning
Semaphore instances should only be created in soft realtime, since the initialisation of a semaphore can not be done in hard realtime.

Definition at line 61 of file Semaphore.hpp.

Constructor & Destructor Documentation

RTT::os::Semaphore::Semaphore ( int  count)
inline

Initialize a Semaphore with an initial count.

See also
value() to retrieve the current count.

Definition at line 70 of file Semaphore.hpp.

RTT::os::Semaphore::~Semaphore ( )
inline

Destroy a Semaphore.

Definition at line 78 of file Semaphore.hpp.

Member Function Documentation

void RTT::os::Semaphore::signal ( )
inline

Raise this semaphore and signal one thread waiting on this semaphore.

Definition at line 96 of file Semaphore.hpp.

bool RTT::os::Semaphore::trywait ( )
inline

Try to wait on this semaphore

Returns
true when the locking succeeded ( this->value() was > 0), false otherwise ( this->value() was = 0 )

Definition at line 106 of file Semaphore.hpp.

int RTT::os::Semaphore::value ( )
inline

Return the current count of this semaphore.

Definition at line 117 of file Semaphore.hpp.

void RTT::os::Semaphore::wait ( )
inline

Lower this semaphore and return if value() is non zero. Or wait if value() is zero until a signal occurs.

Definition at line 87 of file Semaphore.hpp.

Member Data Documentation

rt_sem_t RTT::os::Semaphore::sem
private

Definition at line 64 of file Semaphore.hpp.


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


rtt
Author(s): RTT Developers
autogenerated on Tue Jun 25 2019 19:33:46