How to use a function in a procedure call?

How to use a function in a procedure call?

[Sunny]

Hi all!
I want so set a icon to my frame. Use GtkAda. But when I use the
Set_Icon_From_File(win,"icon.jpg");
An Error said that "can not use function 'Set_Icon_From_File' in a
procedure call"
How to solve the problem? Thanks!

My source code is:
WITH Gtk.Window;USE Gtk.Window;
WITH Gtk.Main;USE Gtk.Main;
WITH Gtk.Enums;USE Gtk.Enums;

PROCEDURE  icon  IS
   win:gtk_window;

BEGIN
   Init;
   Gtk_new(win);
   Set_Size_Request(win,300,200);
   Set_Icon_From_File(win,"icon.jpg");
   Set_Title(win,"Icon");
   Set_Position(win,WIN_POS_CENTER);
   Show(win);
   Main;
END  icon;

Re: How to use a function in a procedure call?

[Dmitry A. Kazakov]

On Fri, 30 Sep 2011 03:41:30 -0700 (PDT), Sunny wrote:

> I want so set a icon to my frame. Use GtkAda. But when I use the
> Set_Icon_From_File(win,"icon.jpg");
> An Error said that "can not use function 'Set_Icon_From_File' in a
> procedure call"
> How to solve the problem? Thanks!

By using the result returned by the function.
 
> My source code is:
> WITH Gtk.Window;USE Gtk.Window;
> WITH Gtk.Main;USE Gtk.Main;
> WITH Gtk.Enums;USE Gtk.Enums;
> 
> PROCEDURE  icon  IS
>    win:gtk_window;
> 
> BEGIN
>    Init;
>    Gtk_new(win);
>    Set_Size_Request(win,300,200);
>    Set_Icon_From_File(win,"icon.jpg");

if not Set_Icon_From_File(win,"icon.jpg") then
   null; -- Or set the default icon instead
end if;

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de

Re: How to use a function in a procedure call?

[Jeffrey Carter]

On 09/30/2011 03:41 AM, Sunny wrote:
> Hi all!
> I want so set a icon to my frame. Use GtkAda. But when I use the
> Set_Icon_From_File(win,"icon.jpg");
> An Error said that "can not use function 'Set_Icon_From_File' in a
> procedure call"

As the msg indicates, Set_Icon_From_File is a function, not a procedure. While 
some languages allow you to silently discard a function result, Ada does not. So 
you must do something with the result of the function call, such as store it in 
a variable, pass it to another subprogram, or use it in an expression.

-- 
Jeff Carter
"I would never want to belong to any club that
would have someone like me for a member."
Annie Hall
41

Re: How to use a function in a procedure call?

[Sunny]

On Oct 1, 3:13 am, Jeffrey Carter <spam.jrcarter....@spam.not.acm.org>
wrote:
> On 09/30/2011 03:41 AM, Sunny wrote:
>
> > Hi all!
> > I want so set a icon to my frame. Use GtkAda. But when I use the
> > Set_Icon_From_File(win,"icon.jpg");
> > An Error said that "can not use function 'Set_Icon_From_File' in a
> > procedure call"
>
> As the msg indicates, Set_Icon_From_File is a function, not a procedure. While
> some languages allow you to silently discard a function result, Ada does not. So
> you must do something with the result of the function call, such as store it in
> a variable, pass it to another subprogram, or use it in an expression.
>
Thanks for your reply. Could you indicate a specified way to solve the
problem? Such as how to store-it in a variable, pass it to another
subprogram, or use it in an expression?
Thank you again!

Re: How to use a function in a procedure call?

[Jeffrey Carter]

On 09/30/2011 08:53 PM, Sunny wrote:
>>
> Thanks for your reply. Could you indicate a specified way to solve the
> problem? Such as how to store-it in a variable, pass it to another
> subprogram, or use it in an expression?

I think you've already seen an example of using it in an expression in an 
earlier post, something like

if Set_Icon_From_File (Win, "icon.jpg") then
    null;
end if;

If we can safely presume from this that it returns Boolean, then you could 
declare a Boolean variable

V : Boolean;

and store the result of the function call in it by means of an assignment.

-- 
Jeff Carter
"I would never want to belong to any club that
would have someone like me for a member."
Annie Hall
41