Re: GTK2 with c++, without gtkmm

[Joaquín Cuenca Abela <cuenca pacaterie u-psud fr>]

On Thu, 2002-12-12 at 22:08, Progss wrote:
> Hi all!
>
> I've been just a reader of this mailing-group, but it seems to me, that
> now I've got a problem which cannot be solved just after reading :)
>
> I'm writing an application using GTK2, however I decided to use
> C++ because of it's objects :) I tried not to pay attention to some
> difficulties, but they return. Type matching is too strict, so after e.g:
>
> [cut]
>     hsep = gtk_hseparator_new();
>     gtk_table_attach(GTK_TABLE(packTable), hsep , 0,2,2,3,
>                                 GTK_FILL|GTK_SHRINK, GTK_FILL, // *** HERE!
>                                 0,0 );
> [cut]

GTK_FILL is a GtkAttachOptions, GTK_SHRINK is a GtkAttachOptions, but
GTK_FILL | GTK_SHRINK is not a GtkAttachOptions (its integer value
doesn't match any of the GtkAttachOptions enumeration).  That's why a
C++ is complaining.

To solve the problem, just add an explicit cast to the GTK_FILL |
GTK_SHRINK part.

> error message is like that:
> ---
> cannot convert `int' to `GtkAttachOptions' for argument
> `7' to `gtk_table_attach (GtkTable *, GtkWidget *, unsigned int, unsigned
> int, unsigned int, unsigned
> int, GtkAttachOptions, GtkAttachOptions, unsigned int, unsigned int)'
> ---
>
> There are also problems when try to call  g_signal_connect()
> passing a static class method as a callback function.
>
> I'm using "gpointer data" to pass extra data, because
> in a static function I cannot access non-static class members.
>
> SOMETHING LIKE AN EXAMPLE:
>
> class Foo {
> public:
>     GtkWidget* button;
>     static void callback(GtkWidget* widget, gpointer data);
>     gint foo2;
> };
>
> [,,,]   g_signal_connect (G_OBJECT (button), "clicked",
>                     G_CALLBACK (callback), (gpointer) this->foo2);

it should be (gpointer) &this->foo2

this->foo2 is an integer (for example 0), and not a valid address.

Cheers,

-- 
Joaquín Cuenca Abela
cuenca pacaterie u-psud fr