Using libsigc++ for events in C++

[skiman1979]

Hi all,

I'm currently working on a C++ console application has a few classes and I wanted to enable certain classes to raise events back to event handlers in main.cpp. I came across libsigc++-2.0 but am having problems actually using it.

It installs just fine on my Ubuntu 9.04 box (both the runtime and dev packages) but I'm not sure what to actually #include in my source code. I tried following the tutorial on the libsigc++ site (Chapter*2.*Connecting your code to signals) but it doesn't give any information on what libsigc++ headers I need.

I think I narrowed it down to #include <sigc++-2.0/sigc++/signals.h>, but I am getting hundreds of compiler errors similar to " '_A_a1_' was not declared in this scope" referencing signal.h.

Following is some code for my class header. I haven't put anything into the implementation file yet, or main.cpp.

#include <pthread>
#include <stdlib>
#include <iostream>
#include <fstream>
using namespace std;

#include <sigc++-2.0/sigc++/signal.h>

class MyClass
{
public:
        MyClass();
        virtual ~MyClass();

        sigc::signal<void,int> MySignal1;
        sigc::signal<void,int> MySignal2;

        void WaitForSomething();  //reads certain files and triggers events
};

My intent was in WaitForSomething() to execute MySignal1.emit() (or MySignal2.emit()), which would be connected to OnMySignalX functions in main.cpp, but that part hasn't been written yet.

On a side note: For some reason, if I remove 'int' from the MySignal1 or MySignal2 declaration (e.g., sigc::signal<void> MySignal1;, the compiler tells me I have an invalid entry for argument 2. I thought signal was supposed to be a wrapper so only the first argument (the template's return type) is required.

[skiman1979]

Anyone? I've tried several approaches here including using versions 1.2 and 2.0 of libsigc++. I can manage to get it to the point where my code compiles, but the signal.h header of libsigc++ generates 750+ compiler errors.

[JHenson]

I compiled using

#include <sigc++/sigc++.h>

in my header file. With

`pkg-config sigc++-2.0 --cflags` with the compiler and
`pkg-config sigc++-2.0 --libs` with the linker

[Rubberman]

Sorry, but I haven't used C++ signal template classes so I can't really help you in this regard. However, usually for C++ event handling one should use C++ exceptions, try/throw/catch. You might want to use sigc::signal<RT,AT> classes to catch external signals (SIGUSR1, SIGKILL, etc), and then throw the appropriate exception to be caught in main().