Re: Set maximum length for text control

[Igor Korot <ikorot01 gmail com>]

Eric,
Here is my corrected code:

static void maxlen_handler(GtkTextBuffer *buffer, GtkTextIter
*location, gchar *text, gint len, gpointer ptr)
{
    text = text;
    len = len;
    ptr = ptr;
    gint count = gtk_text_buffer_get_char_count( buffer );
    if( count > 5 )
    {
        GtkTextIter end;
        gtk_text_buffer_get_end_iter( buffer, &end );
        gtk_text_buffer_delete( buffer, location, &end );
    }
}

Basically what I'm doing is:
I already have the beginning iterator - location, so all I need is the
end iterator, which is
retrieved using gtk_text_buffer_get_end_iter().
Then I am removing the text between location and and end.

However, it doesn't work. I can still see the typing text which more
that 5 symbols.
Running under gdb I see that _buffer_delete() call is executed, but
the text is not being
updated.
I am trying it on GTK+-2.24.

Thank you.

On Wed, Jan 11, 2017 at 2:21 PM,  <cecashon aol com> wrote:
> Check that your callback looks similar to the following.
>
> https://developer.gnome.org/gtk3/stable/GtkTextBuffer.html#GtkTextBuffer-insert-text
>
> It looks like you have "gint WXUNUSED(len), gpointer *user_data" that is
> likely giving you trouble.
>
> A couple of notes about this. It is a good idea to look up the callback in
> the documentation. If you get the parameters wrong your code may compile
> without warning and then later segfault. This is something in C you have to
> be careful of. The compiler might not help you here. Also a gpointer is a
> void* pointer.
>
> https://developer.gnome.org/glib/stable/glib-Basic-Types.html#gpointer
>
> This can cause confusion. When you are using a gpointer *user_data, that is
> a pointer to an array of pointers like a void **user_data or a void
> *user_data[]. That is valid if you are sending to your callback a pointer to
> some array of pointers and you might want to do this. Again, the compiler
> might not be able to help you when using void* pointers and you will
> probably get a segfault if you get it wrong. The documentation has a
> gpointer user_data parameter so that you can pass a pointer of any type to
> your callback along with the other required callback parameters. If you know
> the type of the pointer you can use the type in the callback so the compiler
> can help find potential errors. If you are sending a GRand* to your callback
> you can type it as such. If you are sending a pointer to an array of widget
> pointers you might have something like GtkWidget **widgets or GtkWidget
> *widgets[] although gpointer *widgets will work also and is valid but the
> compiler can't type check it for you.
>
> Eric