error: cannot allocate an object of abstract type 'ClassName'

Giorgi

Hi everyone.

I saw QRunnable examples and I want to test it, but I have an error:
error: cannot allocate an object of abstract type 'TestRunnable'

Why my class TestRunnable which extends QRunnable is abstract?

Here is sample code:

main.cpp

#include <QCoreApplication>
#include "testrunnable.h"

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    
    TestRunnable *task = new TestRunnable();

    return a.exec();
}

testrunnable.h

#ifndef TESTRUNNABLE_H
#define TESTRUNNABLE_H

#include <QRunnable>

class TestRunnable : public QRunnable
{
public:
    TestRunnable();
};

#endif // TESTRUNNABLE_H

testrunnable.cpp

#include "testrunnable.h"

TestRunnable::TestRunnable()
{
}

GrahamL

Hi
You need to override the abstract 'run' method

Jeroentjehome

The name 'abstract' tells the problem. Abstract classes only declare functions that need to be implemented/overwritten before you are able to allocate and use them. So read the QRunnable header file and check out all the virtual functions and overwrite them.

Giorgi

OH yes. thread without run...
thank you.