table of contents
QwtSystemClock(3) | Qwt User's Guide | QwtSystemClock(3) |
NAME¶
QwtSystemClock -QwtSystemClock provides high resolution clock time functions.
SYNOPSIS¶
#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).
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¶
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::restart ()¶
Set the start time to the current timeReturns:
Time, that is elapsed since the previous start
time.
void QwtSystemClock::start ()¶
Sets the start time to the current time.Author¶
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