Re: Compile warning (newbie)

[Richard Boaz <riboaz xs4all nl>]

no need to declare *str, like this:

void edit_changed (GtkWidget *widget, gpointer *data)
{
    gchar *strcopy;

    strcopy = g_strdup(gtk_entry_get_text (GTK_ENTRY (widget)));

    g_print ("Entry changed to %s\n", strcopy);

    g_free(strcopy);
}



On Apr 17, 2007, at 8:09 AM, William D. Tallman wrote:

> On Mon, Apr 16, 2007 at 05:01:29PM -0600, Michael L Torrie wrote:
> > On Tue, 2007-04-17 at 08:22 +1000, Andrew Cowie wrote:
> > > Return type of gtk_entry_get_text() is (const gchar*), not just
> > > (gchar*). You discarded the const qualifier when assigning the  
> > > result to
> > > str.
> > >
> > > Just declare str with const.
> >
> > The reason why this is important is because gtk_entry_get_text is
> > returning you just a pointer to a buffer inside the widget.   
> > Therefore
> > you should never modify it.  If you do, you run the risk of  
> > crashing the
> > program.  That's why the return type is const and the compiler  
> > gives you
> > a warning.
> >
> > If you want to do something to the string you need to copy it with
> > g_strdup, remembering to free your copy when you are done.
> >
> > Michael
>
> Then it should be like this?
>
> void edit_changed (GtkWidget *widget, gpointer *data)
> {
>     const gchar *str;
>     gchar *strcopy;
>
>     str = gtk_entry_get_text (GTK_ENTRY (widget));
>
>     strcopy = g_strdup(str);
>
>     g_print ("Entry changed to %s\n", strcopy);
>
>     free(strcopy);
> }
>
> I'm no whiz with C itself and have never used strdup.  IIUC, the
> template is as above, replacing the g_print with whatever is to be  
> done
> with the copied string.  Is that correct?  If not, what don't I
> understand here?
>
> Thanks,
>
> Bill Tallman
>
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