create and emit gtk signal

c, gtk, signals

Solution

The GObject library provides some builtin marshallers, so your code should probably be:

g_signal_new("child-finished",
             G_TYPE_OBJECT, G_SIGNAL_RUN_FIRST,
             0, NULL, NULL,
             g_cclosure_marshal_VOID__POINTER,
             G_TYPE_NONE, 1, G_TYPE_POINTER);

or, if you want type checking:

g_signal_new("child-finished",
             G_TYPE_OBJECT, G_SIGNAL_RUN_FIRST,
             0, NULL, NULL,
             g_cclosure_marshal_VOID__BOXED,
             G_TYPE_NONE, 1, GDK_TYPE_EVENT);

The parameters of the signal handler must be present (the object itsself is implied), so be sure to specify a pointer (as in the first example) or a boxed type (as in the second example).

If the marshaller you need is not present in the builtins ones, you could use the glib-genmarshal utility or directly code it by yourself (it is quite trivial, just checkout the output of glib-genmarshal).

Problem

I am trying to create and emit a GTK signal: ``` g_signal_new("child-finished", G_TYPE_OBJECT, G_SIGNAL_RUN_FIRST, 0, NULL, NULL, NULL, // *** I think this is where I need to change it G_TYPE_NONE, 0); g_signal_connect(G_OBJECT(myWindow), "child-finished", G_CALLBACK(MyCallback), NULL); ``` Here is my code that emits the signal: ``` gtk_signal_emit_by_name(referenceToMyWindow, "child-finished"); ``` And here is my code that handles the signal: ``` void MyCallback(GtkWidget *w, GdkEvent *e) { // handler code here } ``` When I run the code I get the following error: GLib-GObject-CRITICAL **: g`_closure_`invoke: assertion `closure->marshal || closure->meta_marshal' failed I know it has something to do with passing a marshaller to the `g_signal_new` function, but I don't know what a marshaller is, I can't understand the documentation, and the examples online are few and far between. How do I declare and connect my own signal?

Original source