QwtSystemClock provides high resolution clock time functions. More...

#include <qwt_system_clock.h>

Public Member Functions
	QwtSystemClock ()
	Constructs a null clock object.

virtual	~QwtSystemClock ()
	Destructor.

bool	isNull () const

void	start ()

double	restart ()

double	elapsed () const

Detailed Description

QwtSystemClock provides high resolution clock time functions.

Sometimes the resolution offered by QTime ( millisecond ) is not accurate enough for implementing time measurements ( f.e. sampling ). QwtSystemClock offers a subset of the QTime functionality using higher resolution timers ( if possible ).

Precision and time intervals are multiples of milliseconds (ms).

( QwtSystemClock is obsolete since Qt 4.8 as QElapsedTimer offers the same precision )

Note: The implementation uses high-resolution performance counter on Windows, mach_absolute_time() on the Mac or POSIX timers on other systems. If none is available it falls back on QTimer.

Member Function Documentation

◆ elapsed()

double QwtSystemClock::elapsed ( ) const

Returns: Number of milliseconds that have elapsed since the last time start() or restart() was called or 0.0 for null clocks.

◆ isNull()

bool QwtSystemClock::isNull ( ) const

Returns: true if the clock has never been started.

◆ restart()

double QwtSystemClock::restart ( )

Set the start time to the current time

Returns: Time, that is elapsed since the previous start time.

◆ start()

void QwtSystemClock::start ( )