QwtSystemClock Class Reference

#include <qwt_system_clock.h>

List of all members.

Public Member Functions
double	elapsed () const
bool	isNull () const
	QwtSystemClock ()
double	restart ()
void	start ()
virtual	~QwtSystemClock ()
Static Public Member Functions
static double	precision ()

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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).

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.

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Constructor & Destructor Documentation

QwtSystemClock::QwtSystemClock

(

)

Constructs a null clock object.

QwtSystemClock::~QwtSystemClock

(

)

[virtual]

Destructor.

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Member Function Documentation

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.

bool QwtSystemClock::isNull

(

)

const

Returns:

true if the clock has never been started.

double QwtSystemClock::precision

(

)

[static]

Returns:

Accuracy of the system clock in milliseconds.

double QwtSystemClock::restart

(

)

The start time to the current time and return the time, that is elapsed since the previous start time.

void QwtSystemClock::start

(

)

Sets the start time to the current time.