QwtSystemClock Class Reference

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

#include <qwt_system_clock.h>

Classes
class	PrivateData

Public Member Functions
double	elapsed () const
bool	isNull () const
	QwtSystemClock ()
	Constructs a null clock object. More...
double	restart ()
void	start ()
virtual	~QwtSystemClock ()
	Destructor. More...

Private Attributes
PrivateData *	d_data

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( QwtSystemClock is obsolete since Qt 4.8 as QElapsedTimer offers the same precision )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

Definition at line 33 of file qwt_system_clock.h.

Constructor & Destructor Documentation

QwtSystemClock::QwtSystemClock

(

)

Constructs a null clock object.

Definition at line 309 of file qwt_system_clock.cpp.

QwtSystemClock::~QwtSystemClock ( )

virtual

Destructor.

Definition at line 321 of file qwt_system_clock.cpp.

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.

Definition at line 376 of file qwt_system_clock.cpp.

bool QwtSystemClock::isNull

(

)

const

Returns

true if the clock has never been started.

Definition at line 332 of file qwt_system_clock.cpp.

double QwtSystemClock::restart

(

)

Set the start time to the current time

Returns

Time, that is elapsed since the previous start time.

Definition at line 362 of file qwt_system_clock.cpp.

void QwtSystemClock::start

(

)

Sets the start time to the current time.

Definition at line 345 of file qwt_system_clock.cpp.

Member Data Documentation

PrivateData* QwtSystemClock::d_data

private

Definition at line 48 of file qwt_system_clock.h.

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

• qwt_system_clock.h
• qwt_system_clock.cpp