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 time

       Returns:
           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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