Passing additional arguments to gtk function

Question

I\'m trying to learn how to make GUIs using gtk+ 3.0. I want to pass a simple argument, an integer, to a callback function, so that when I press the button the value of the

Answer 1

There are a bunch of useful macros which store an integer (32bit, no longer!) into a pointer.

int a = 42;
gpointer ptr = GINT_TO_POINTER (a)
//GUINT_TO_POINTER (a), GBOOLEAN_TO_POINTER (a), GSIZE_TO_POINTER (a)

reverse:

int a2 = GPOINTER_TO_INT (ptr);
//GPOINTER_TO_UINT (ptr), GPOINTER_TO_...