Fortran bind with C++/Qt : QTimer issue “QObject::startTimer: QTimer can only be used with threads started with QThread”

I need to create a simple Fortran program to be bound with a complex Qt program.

The only problem I meet is the utilization of QTimer (which is mandatory): when I call a function using QTimer from Fortran, I always get this error message:

QObject::startTimer: QTimer can only be used with threads started with QThread.

All the other "complex" stuff (QUdpSocket, utilization of classes..) work properly.

How could I solve this problem? After the error message, I think I should find a trick to use QThread for Fortran but I have no idea how to do. (I also tried to inherit dummy from QThread instead of QObject : does not work either)

Here is a simple example. I give now the output and after, the source code.

output when the C++/Qt program is directly launched

begin
hello
end
hello
hello
... // one "hello" per second

output when the f90 program is launched

begin
QObject::startTimer: QTimer can only be used with threads started with QThread
end

main.cpp

#include <QApplication>
#include <QtGui>
#include "dummyclass.hpp"

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    DummyClass*ds = new DummyClass();
    Q_UNUSED(ds);
    return app.exec();
}

dummyclass.hpp

#include <QTimer>
#include <QObject>
#include <QApplication>
#include <QTextStream>

class dummyclass : public QObject // public QThread
{
    Q_OBJECT

    public:
        DummyClass();

    private:
        QTimer timer;

    private slots:
        void hello();
}

dummyclass.cpp

#include "dummyclass.hpp"

DummyClass::DummyClass()
{
     QTextStream(stdout) << "begin" << endl;
     connect(&timer, SIGNAL(timeout()), this, SLOT(hello()));
     timer.start(1000);
     QTextStream(stdout) << "endl" << endl;
}

void DummyClass::hello()
{
    QTextStream(stdout) << "Hello !" << endl;
}

dummymain.f90

program dummy_main

use dummy_module
    use, intrinsic :: ISO_C_Binding, only: C_CHAR, C_NULL_CHAR
type(dummy_type) :: dummy

call newDummy(dummy)
end program dummy_main

dummy_module.f90

module dummy_module

    use, intrinsic :: ISO_C_Binding, only: C_CHAR, C_NULL_CHAR
    use, intrinsic :: ISO_C_Binding, only: C_ptr, C_NULL_ptr

    implicit none

    private
        type dummy_type
            private
            type(C_ptr) :: object = C_NULL_ptr
        end type dummy_type
    !------------------------
    ! C function declarations
    !------------------------

    interface

        function C_dummyClass__new_ () result(this) bind(C,name="dummyClass__new_")
            import
            type(C_ptr) :: this
        end function C_dummyClass__new_

        subroutine C_dummyClass__delete_ (this) bind(C,name="dummyClass__delete_")
            import
            type(C_ptr), value :: this
        end subroutine C_dummyClass__delete_

    end interface

    interface newDummy
        module procedure newDummy__new
    end interface newDummy

    interface deleteDummy
        module procedure dummyClass__delete
    end interface deleteDummy

    public :: newDummy, deleteDummy

    !------------------------------------------------------------------------------
    CONTAINS
    !------------------------------------------------------------------------------

    !-------------------------------------------------
    ! Fortran wrapper routines to interface C wrappers
    !-------------------------------------------------

    subroutine dummyClass__new(this)
        type(dummy_type), intent(out) :: this
        this%object = C_dummyClass__new_()
    end subroutine dummyClass__new

    subroutine dummyClass__delete(this)
        type(dummy_type), intent(inout) :: this
        call C_dummyClass__delete_(this%object)
        this%object = C_NULL_ptr
    end subroutine dummyClass__delete

    !------------------------------------------------------------------------------

end module dummy_module

compilation

g++ -fPIC -Wall -Wextra -DQT_NO_DEBUG -DQT_GUI_LIB -DQT_CORE_LIB -DQT_SHARED -lQtGui -lQtCore -lQtNetwork -lpthread -I/usr/include/QtGui -I/usr/include/Qt -I/usr/include/QtCore -I/usr/include/QtNetwork -c *.cpp

gfortran -c *.f90

gfortran -Wall -Wextra -DQT_NO_DEBUG -DQT_GUI_LIB -DQT_CORE_LIB -DQT_SHARED -lQtGui -lQtCore -lQtNetwork -lpthread -I/usr/include/QtGui -I/usr/include/Qt -I/usr/include/QtCore -I/usr/include/QtNetwork -o dummy *.o /home/me/build/dummy/src/moc_dummy_class_.cxx -lstdc++

(note: the moc file for dummy class was already generator by QtCreator)