Re: sigc::ptr_fun() compiler error

[Bob Caryl <bob fis-cal com>]

Ron Lockwood-Childs wrote:

> Hello,
>
> I get an error when trying to compile the following code:
>
> test.h
> ------
> #include <libglademm/xml.h>
> #include <gtkmm>
> #include <iostream>
>
> class Test
> {
>   Glib::RefPtr<Gnome::Glade::Xml> refXml;
>   Gtk::Window *pMWindow;
>   void on_quit_activate() { if (pMWindow) pMWindow->hide(); }
> public:
>   Test( int argc, char **argv, char *glade_path );
> };
>
> test.cc
> -------
> #include <libglademm/xml.h>
> #include <gtkmm>
> #include <iostream>
> #include "test.h"
>
> Test::Test( int argc, char **argv, char *glade_path )
> {
>   try
>   {
>     refXml = Gnome::Glade::Xml::create( glade_path );
>   }
>   catch(const Gnome::Glade::XmlError& ex)
>   {
>     std::cerr << ex.what() << std::endl;
>     exit( 1 );
>   }
>
>   refXml->get_widget("mainwindow", pMWindow);
>   if (pMWindow)
>   {
>       Gtk::MenuItem* pMenuItem = 0;
>       refXml->get_widget("menu_file_quit", pMenuItem);
>       if(pMenuItem)
>       {
>         pMenuItem->signal_activate().connect(
>           sigc::ptr_fun( &Test::on_quit_activate ) );
>       }
>   }
> }
>
> int main( argc, argv )
> {
>   Test testDialog = new Test( argc, argv, "test.glade" );
>   return 0;
> }
>
> ---------
> (if I've made copy-paste errors, FWIW the actual code doesn't get 
> syntax errors..)
>
> Finally, when I attempt compilation, this is what I get:
>
> $ g++ test.cc -o test `pkg-config gtkmm-2.4 --cflags --libs` 
> -lglademm-2.4
> test.cc: In constructor `Test::Test(int, char**, char*)':
> test.cc: error: no matching function for call to `ptr_fun(void 
> (Test::*)())'
>
> This was taken from the tutorial, except that now I'm attempting to 
> put the UI code into its own class.  It gives me no hint on why it 
> can't find the function.  If I do anything to the function pointer, 
> such as:
> sigc::ptr_fun(&(Test::on_quit_activate))
> or
> sigc::ptr_fun(&(this->on_quit_activate))
> I get the same error, with another complaint regarding ANSI C++ and 
> pointers to non-static member functions.  This signal handler must be 
> a member function, since it accesses private data.
>
> Anyone seen this or similar errors & can offer help?  I'd appreciate it.
>
> --
> Ron Lockwood-Childs
> _______________________________________________
> gtkmm-list mailing list
> gtkmm-list gnome org
> http://mail.gnome.org/mailman/listinfo/gtkmm-list
Your compiler is unhappy because you are trying to pass a class member 
function to sigc::ptr_fun when it is expecting a NON class member 
function.  Try using sigc::mem_fun with the following syntax to pass 
your member function:

pMenuItem->signal_activate().connect( sigc::mem_fun( *this, 
&Test::on_quit_activate ) );

I hope this helps you out.

Bob Caryl