GTK：回调函数签名概述

Question

In a GTK2 application a user-defined callback function can be called when certain events occur, eg, like this:

static void on_destroy(GtkObject* o) {
    gtk_main_quit();
}

int main(int argc, char * argv[]) {
    ...    
    g_signal_connect(window1, "destroy", G_CALLBACK(on_destroy), NULL);
    ...
}

The signature of the callback functions depends on the type of signal or event. I was looking for an concise overview of those signatures and I found a chapter about signals in the GTK+ 2.0 tutorial . However, it seems to be missing the callback signatures for the GtkTreeview signals, like row-activated , select-cursor-row etc.

Are there any other sources that describe the correct implementation of all callback signatures, preferably in a concise overview and not spread out over several chapters?

Answer 1

You should check the Gtk+ 2 Reference Manual

For example, the destroy signal being connected in your example comes from one of the GtkWindow parent classes, GtkObject

The “destroy” signal

void user_function (GtkObject *object, gpointer user_data)

Check the Tree, List Widgets for relevant signals and respective prototypes:

https://developer.gnome.org/gtk2/stable/TreeWidgetObjects.html

Notice: Parent classes doesn't mean multiple inheritance, just a class above in the inheritance hierarchy.

Answer 2

You need to learn how to use the official help. On each widget help page, there's a navigation bar at the top. There you have direct links to the signals, the object hierarchy (parent classes), etc.

So if you're looking for a specific signal for a widget, you just go to that widget help page, then click on the "signals" link in the navigation bar. If the signal is not there, then it must be in a parent class. So you click on the "object hierarchy" link which sends you to the widget's inheritance tree. You click ont its parent and search for the signal again.

Alternatively, you may install the devhelp help browser that comes installed with your Linux distro (or in MSYS2 for Windows). There is a search field where you can just type the name of the symbol you're looking for, signals included.