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.TH "QwtSystemClock" 3 "Thu Dec 11 2014" "Version 6.1.2" "Qwt User's Guide" \" -*- nroff -*-
.ad l
.nh
.SH NAME
QwtSystemClock \-
.PP
\fBQwtSystemClock\fP provides high resolution clock time functions\&.
.SH SYNOPSIS
.br
.PP
.PP
\fC#include <qwt_system_clock\&.h>\fP
.SS "Public Member Functions"
.in +1c
.ti -1c
.RI "\fBQwtSystemClock\fP ()"
.br
.RI "\fIConstructs a null clock object\&. \fP"
.ti -1c
.RI "virtual \fB~QwtSystemClock\fP ()"
.br
.RI "\fIDestructor\&. \fP"
.ti -1c
.RI "bool \fBisNull\fP () const "
.br
.ti -1c
.RI "void \fBstart\fP ()"
.br
.ti -1c
.RI "double \fBrestart\fP ()"
.br
.ti -1c
.RI "double \fBelapsed\fP () const "
.br
.in -1c
.SH "Detailed Description"
.PP
\fBQwtSystemClock\fP provides high resolution clock time functions\&.
Sometimes the resolution offered by QTime ( millisecond ) is not accurate enough for implementing time measurements ( f\&.e\&. sampling )\&. \fBQwtSystemClock\fP offers a subset of the QTime functionality using higher resolution timers ( if possible )\&.
.PP
Precision and time intervals are multiples of milliseconds (ms)\&.
.PP
\fBNote:\fP
.RS 4
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\&.
.RE
.PP
.SH "Member Function Documentation"
.PP
.SS "double QwtSystemClock::elapsed () const"
.PP
\fBReturns:\fP
.RS 4
Number of milliseconds that have elapsed since the last time \fBstart()\fP or \fBrestart()\fP was called or 0\&.0 for null clocks\&.
.RE
.PP
.SS "bool QwtSystemClock::isNull () const"
.PP
\fBReturns:\fP
.RS 4
true if the clock has never been started\&.
.RE
.PP
.SS "double QwtSystemClock::restart ()"
Set the start time to the current time
.PP
\fBReturns:\fP
.RS 4
Time, that is elapsed since the previous start time\&.
.RE
.PP
.SS "void QwtSystemClock::start ()"
Sets the start time to the current time\&.
.SH "Author"
.PP
Generated automatically by Doxygen for Qwt User's Guide from the source code\&.
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