Re: Transmit an array to a function

[amw18 home com]

Raymond Wan wrote:
> 
> Hi,
> 
> On Thu, 5 Jul 2001, Anthony Ferrand wrote:
> > > I'm not sure about it but try this :
> > > gtk_signal_connect (GTK_OBJECT(button),"clicked",GTK_SIGNAL_FUNC(function),
> > > widget);
> > > according that widget is the name of your array (GtkWidget *widget[20])
> > > This should work, I think (thought I never tried it...)
> 

When I see the word 'transmit' I wonder if you are taking advantage of
the most useful aspect of a pointer.

You may be doing the best thing already, but in case you are not. . .

In most cases (especially when the array or struct is large) you prefer
not to
copy the array into the function, but only to pass the address of the
array
into the function so that the array continues to be accessible inside
the
function (as it was before the function).  When this can be done it
saves
the time of copying the array to a new place in memory and saves the
space
in memory.

The way to do this is to put the address of the array into a gpointer
(or a void pointer or any generic pointer designed to be large enough to
hold all pointer sizes), pass the gpointer into the function as an
argument 
and within the function put the address back into a pointer of the
desired type.

Once you have the address of the array inside the function in a pointer
with a type, you can access the array using that pointer.

The 4th argument of the function  gtk_signal_connect() is a gpointer
designed to do exactly this.

I'm new to GTK+, but as a long-time C programmer I recognized the value
of
this code immediately.

amw18