thanks for the response.

I have spent my afternoon in it and the socket looks an importante notion but i haven't yet understood how use it.

just to be sure : i can't connect a thread just like that ?
int main()
{
MyThread a;
MyThread b;
a.start();
b.start();
QObject::connect(a, SIGNAL(thekey()), b, SLOT(recep()));

error:
tread.cpp: In function «int main()»:
tread.cpp:44: erreur: incomplete type «QObject» used in nested name specifier
tread.cpp:45: erreur: incomplete type «QObject» used in nested name specifier

that would be very easy.

i will try the socket thank you for your help