bmptk::rtos::waitable Class Reference

abstract thing that a task can wait for More...

#include <rtos.h>

Inheritance diagram for bmptk::rtos::waitable:

Public Member Functions
virtual void	clear ()
	clear the waitable
Public Member Functions inherited from bmptk::rtos::event
void	print (std::ostream &s, bool header) const
	prints an event, for debugging only
bool	operator== (const event &rhs) const
	report wether two events are the same
bool	operator== (const waitable &rhs) const
	report whether an event corresponds to a waitable
bool	operator!= (const event &rhs) const
	report wether two events are not the same
bool	operator!= (const waitable &rhs) const
	report whether an event does not correspond to a waitable
event	operator+ (const event &rhs) const
	add two waitables, result can be used in a wait() call

Protected Member Functions
	waitable (task *task, const char *name)
	constructor, specify owner and name
void	set ()
	set the waitable

Friends
class	waitable_set

Detailed Description

abstract thing that a task can wait for

Waitable is an abstract class (there are no objects that are just a waitable). flag, timer, clock and channel are concrete classes that inherit from waitable. A waitable is always created for a particular task. A maximum of 31 waitables can be created for each task. (Actually the maximum is 32, but one waitable is created internally to implement the rtos-version of the wait() call.) A waitable can be two states: set or cleared. A waitable is initially cleared.

A task can wait for one, a subset, or all waitables created for it. The default is to wait for all waitables created for the task, the other variants are specified by supplying to the task:wait() call either a single waitable, or the sum (operator+) of the waitables you want to wait for. When one of the waitables that is waited for is or becomes set the wait() call clears that waitable and returns an event that compares equal to the waitable. (Note that some waitables, for instance the channel, can immediately set itself again.) The calling task can compare that event to the waitables to see which event happened. When more than one of the waited-for waitables is set the wait() call makes an arbitrary choice from these waitables.

The operation clear() is provided (virtual, the default only clears the waitable) set() is provided but private (not all waitables can be set by the user).

Definition at line 218 of file rtos.h.

Constructor & Destructor Documentation

bmptk::rtos::waitable::waitable ( task *  task, const char *  name  )

protected

constructor, specify owner and name

The name is used for debugging only.

Member Function Documentation

virtual void bmptk::rtos::waitable::clear ( )

virtual

clear the waitable

This is automatically done when the waitable causes a task::wait() call to return it.

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

• core/rtos.h