OsMutexBase Class Reference

Mutual exclusion semaphore (mutex) More...

#include <OsMutex.h>

Inheritance diagram for OsMutexBase:

Collaboration diagram for OsMutexBase:

Public Types
enum	MutexOptions { Q_FIFO = 0x0, Q_PRIORITY = 0x1, DELETE_SAFE = 0x4, INVERSION_SAFE = 0x8 }

Public Member Functions
virtual OsStatus	acquire (const OsTime &rTimeout=OsTime::OS_INFINITY)=0
	Block the task until the mutex is acquired or the timeout expires. More...
virtual OsStatus	tryAcquire (void)=0
	Conditionally acquire the mutex (i.e., don't block) More...
virtual OsStatus	release (void)=0
	Release the mutex. More...
virtual void	OsMutexShow (void)=0
	Print mutex information to the console. More...
Public Member Functions inherited from OsSyncBase
virtual	~OsSyncBase ()
	Destructor. More...
OsSyncBase &	operator= (const OsSyncBase &rhs)
	Assignment operator. More...

Protected Member Functions
	OsMutexBase ()
	Default constructor. More...
virtual	~OsMutexBase ()
	Destructor. More...
Protected Member Functions inherited from OsSyncBase
	OsSyncBase ()
	Default constructor. More...

Detailed Description

Mutual exclusion semaphore (mutex)

The mutual-exclusion semaphore is a specialized version of the binary semaphore, designed to address issues inherent in mutual exclusion, such as recursive access to resources, priority inversion, and deletion safety.

The fundamental behavior of the mutual-exclusion semaphore is identical to that of a binary semaphore except for^

• It can only be used for mutual exclusion and it can only be released by the task that acquired it.
• If a thread already holds the mutex, it may acquire it again without first releasing it. The thread must release the mutex as many times as it has acquired it before the mutex is free to be acquired by another thread.

Member Enumeration Documentation

enum MutexOptions

Enumerator
Q_FIFO	queue blocked tasks on a first-in, first-out < basis
Q_PRIORITY	queue blocked tasks based on their priority
DELETE_SAFE	protect a task that owns the mutex from < unexpected deletion
INVERSION_SAFE	protect the system from priority inversion: NOTE < VxWorks requires Q_PRIORITY with this.

Constructor & Destructor Documentation

OsMutexBase ( )

inlineprotected

Default constructor.

virtual ~OsMutexBase ( )

inlineprotectedvirtual

Destructor.

Member Function Documentation

virtual OsStatus acquire ( const OsTime &  rTimeout = OsTime::OS_INFINITY )

pure virtual

Block the task until the mutex is acquired or the timeout expires.

Implements OsSyncBase.

Implemented in OsMutexWnt, and OsMutexLinux.

virtual OsStatus tryAcquire ( void  )

pure virtual

Conditionally acquire the mutex (i.e., don't block)

Implements OsSyncBase.

Implemented in OsMutexWnt, and OsMutexLinux.

virtual OsStatus release ( void  )

pure virtual

Release the mutex.

Returns

OS_BUSY if the mutex is held by some other task

Implements OsSyncBase.

Implemented in OsMutexWnt, and OsMutexLinux.

virtual void OsMutexShow ( void  )

pure virtual

Print mutex information to the console.

Implemented in OsMutexWnt, and OsMutexLinux.