---
name: "QwtSamplingThread"
section: "3"
platform: "linux"
package: "libqwt-doc"
version: "6.1.4-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/QwtSamplingThread"
---

# QwtSamplingThread(3)

A thread collecting samples at regular intervals.

## NAME

QwtSamplingThread - A thread collecting samples at regular intervals.

## SYNOPSIS

`#include <qwt_sampling_thread.h>`

Inherits QThread.

### Public Slots

void **setInterval** (double **interval**)\
 void **stop** ()\

### Public Member Functions

virtual **~QwtSamplingThread** ()\
 Destructor.  double **interval** () const\
 double **elapsed** () const\

### Protected Member Functions

**QwtSamplingThread** (QObject \*parent=NULL)\
 Constructor.  virtual void **run** ()\
 virtual void **sample** (double **elapsed**)=0\

## Detailed Description

A thread collecting samples at regular intervals.

Continuous signals are converted into a discrete signal by collecting samples at regular intervals. A discrete signal can be displayed by a **QwtPlotSeriesItem** on a **QwtPlot** widget.

**QwtSamplingThread** starts a thread calling periodically **sample()**, to collect and store ( or emit ) a single sample.

**See also:**

**QwtPlotCurve**, **QwtPlotSeriesItem**

## Member Function Documentation

### double QwtSamplingThread::elapsed () const

**Returns:**

Time (in ms) since the thread was started

**See also:**

QThread::start(), **run()**

### double QwtSamplingThread::interval () const

**Returns:**

Interval (in ms), between 2 calls of **sample()**

**See also:**

**setInterval()**

### void QwtSamplingThread::run ()` [protected]`, ` [virtual]`

Loop collecting samples started from QThread::start()

**See also:**

**stop()**

### virtual void QwtSamplingThread::sample (double elapsed)` [protected]`, ` [pure virtual]`

Collect a sample

**Parameters:**

*elapsed* Time since the thread was started in milliseconds

### void QwtSamplingThread::setInterval (double interval)` [slot]`

Change the interval (in ms), when **sample()** is called. The default interval is 1000.0 ( = 1s )

**Parameters:**

*interval* Interval

**See also:**

**interval()**

### void QwtSamplingThread::stop ()` [slot]`

Terminate the collecting thread

**See also:**

QThread::start(), **run()**

## Author

Generated automatically by Doxygen for Qwt User's Guide from the source code.