newbe question about signals / slots

[Walsi]

Hello!

At first a have to say:

.) i am a newb at writing programs in C++
.) i am a newb at Qt
.) i am a newb at OOP

My question: How can I emit a signal out from another function? I think that i have to tedliver someting about the parameters of the functin????

Imagine: I have a SIP Client in C++ (pjsip.org) and I want to build a Application (GUI) on this Client.

So when I (the SIP Client) is called, it comes to a callback function in which the call is handeld. Now i want to see it on the GUI when I get called.

My idea: I program a signal Slot unit:
Signal: --> is in the Callback function --> incomingCall();
and in the Slot: --> I enable some buttons for example.

#include "uscinterface.h"     <-- here in this include it the prototyp of the class which  contains the signal
 
static void on_incoming_call(...)
{
...
...
...
 
 
emit incomingCallsignal();
}

#include "uscinterface.h"     <-- here in this include it the prototyp of the class which  contains the signal

static void on_incoming_call(...)
{
...
...
...


emit incomingCallsignal();
}

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Error message at compiling:

error: 'incomingCallsignal' was not declared in this scope


So what is my mistake, or what is the right way to solve this problem
If you need more information or sourcecode to help me, let me know

Best Regards,...