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ost::TimerPort(3) Library Functions Manual ost::TimerPort(3)

NAME

ost::TimerPort - Timer ports are used to provide synchronized timing events when managed under a 'service thread' such as SocketService.

SYNOPSIS

#include <thread.h>

Inherited by ost::SerialPort, and ost::SocketPort.

Public Member Functions


TimerPort ()
Create a timer, mark it as inactive, and set the initial 'start' time to the creation time of the timer object. void setTimer (timeout_t timeout=0)
Set a new start time for the object based on when this call is made and optionally activate the timer for a specified number of milliseconds. void incTimer (timeout_t timeout)
Set a timeout based on the current time reference value either from object creation or the last setTimer(). void decTimer (timeout_t timeout)
Adjust a timeout based on the current time reference value either from object creation or the last setTimer(). void sleepTimer (void)
Sleep until the current timer expires. void endTimer (void)
This is used to 'disable' the service thread from expiring the timer object. timeout_t getTimer (void) const
This is used by service threads to determine how much time remains before the timer expires based on a timeout specified in setTimer() or incTimer(). timeout_t getElapsed (void) const
This is used to determine how much time has elapsed since a timer port setTimer benchmark time was initially set.

Detailed Description

Timer ports are used to provide synchronized timing events when managed under a 'service thread' such as SocketService.

This is made into a stand-alone base class since other derived libraries (such as the serial handlers) may also use the pooled 'service thread' model and hence also require this code for managing timing.

Author

David Sugar dyfet@ostel.com

synchronized millisecond timing for service threads.

Constructor & Destructor Documentation

ost::TimerPort::TimerPort ()

Create a timer, mark it as inactive, and set the initial 'start' time to the creation time of the timer object. This allows 'incTimer' to initially refer to time delays relative to the original start time of the object.

Member Function Documentation

void ost::TimerPort::decTimer (timeout_t timeout)

Adjust a timeout based on the current time reference value either from object creation or the last setTimer(). This reference can be used to time synchronize realtime data over specified intervals and force expiration when a new frame should be released in a synchronized manner.

Parameters

timeout delay in milliseconds from reference.

void ost::TimerPort::endTimer (void)

This is used to 'disable' the service thread from expiring the timer object. It does not effect the reference time from either creation or a setTimer().

timeout_t ost::TimerPort::getElapsed (void) const

This is used to determine how much time has elapsed since a timer port setTimer benchmark time was initially set. This allows one to use setTimer() to set the timer to the current time and then measure elapsed time from that point forward.

return time elapsed in milliseconds, or TIMEOUT_INF if inactive.

timeout_t ost::TimerPort::getTimer (void) const

This is used by service threads to determine how much time remains before the timer expires based on a timeout specified in setTimer() or incTimer(). It can also be called after setting a timeout with incTimer() to see if the current timeout has already expired and hence that the application is already delayed and should skip frame(s).

return time remaining in milliseconds, or TIMEOUT_INF if inactive.

void ost::TimerPort::incTimer (timeout_t timeout)

Set a timeout based on the current time reference value either from object creation or the last setTimer(). This reference can be used to time synchronize realtime data over specified intervals and force expiration when a new frame should be released in a synchronized manner.

Parameters

timeout delay in milliseconds from reference.

void ost::TimerPort::setTimer (timeout_t timeout = 0)

Set a new start time for the object based on when this call is made and optionally activate the timer for a specified number of milliseconds. This can be used to set the starting time of a realtime session.

Parameters

timeout delay in milliseconds from 'now'

void ost::TimerPort::sleepTimer (void)

Sleep until the current timer expires. This is useful in time syncing realtime periodic tasks.

Author

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Sun Dec 27 2020 GNU CommonC++