RE: RES: [Dev-C++] Re: 10 quick questions

[<ech...@ne...>]

"Daniel K. O." <dan...@ya...> wrote:

>Thanks Evan
>
>It solved the problems with missing headers.
>
>But I'm still having some problems:
>
>
>   2)) Look to this error:
>   "144 callbacks.c
>       warning: passing arg 2 of `create_dir_browser' discards qualifiers
>from
>       pointer target type"
>
>   Here is the code:
>   ///
>   /* Function prototype */
>   7: GtkWidget *create_dir_browser(gchar * title, gchar * current_path,
>                    GtkSelectionMode mode, void (*handler) (gchar *));
>
>   124: void on_dir_select29(gchar * dir);
>
>   ...
>
>   141:  GtkWidget *win;
>   142:
>   143:  win = create_dir_browser(_("Select Directory"), g_get_home_dir(),
>   144:               GTK_SELECTION_SINGLE, on_dir_select29);
>   ///
>
>   I get this error in many other points too. I have no idea of what to do
>   (what does the "void (*handler) (gchar *)" mean?).

I would try casting the second argument to (gchar*):
    win = create_dir_browser(_("Select Directory"), (gchar*)g_get_home_dir(),
              GTK_SELECTION_SINGLE, on_dir_select29);


I believe this error occures because the appliction was orrginally written in C which is less strict with it's type checking than C++.  A type cast is probobly all you need.

gtk is a C library orrignaly written on linux but later ported to acouple different OSes, it is roughly equvilant to the gui libs for widows except I think that those are written in C++.

"void (*handler) (gchar *)"  means a function pointer to a function of taking a gchar* and returning void.
on_dir_select29 should be a function of this type.

Ex: 
void my_handler(gchar* variable){
  // do something
}

int main(){
  void (*handler)(gchar*);   // a function pointer

  handler = my_handler;    // initialize pointer     note: a function name is treated as a pointer here - no need to dereference

  handler(gchar_ptr_variable);  // user pointer

}


I don't know why the linker errors are occuring, they might go away after the fixes above, if not I would need to see the code where the erors occure.

Evan

PS  What kind of app are you porting?


>
>
>
>
>
>Well, commenting those lines, it compiles, but then I get linker errors:
>
>c:/projects/lopster/global.o: In function `user2_compare':
>//c/projects/lopster/src/global.c:5452: undefined reference to
>`inet_network'
>
>c:/projects/lopster/search.o: In function `search_fields_detach':
>//c/projects/lopster/src/search.c:2117: undefined reference to
>`gtk_window_reposition'
>
>
>
>
>My objects included:
>
>-lgtk.dll -lgdk-win32-2.0.dll -lgmodule-2.0.dll -lgobject-2.0.dll -lglib-2.0
>.dll -lwininet -lwsock32 -lgtk-win32-1.3.dll C:\Dev-C++\Lib\gtk.lib
>C:\Dev-C++\Lib\gtk-win32-1.3.lib -lc -lmswsock -lgtk-win32-2.0.dll
>C:\Dev-C++\Lib\gtk-win32-2.0.lib
>
>
>
>Again, thanks for any help.
>
>
>
>
>
>
>Daniel K. O.
>
>
>
>-----Mensagem original-----
>De: dev...@li...
>[mailto:dev...@li...]Em nome de Evan Hempel
><ech...@ne...>
>Enviada em: sexta-feira, 5 de abril de 2002 16:23
>Para: "Dev-Cpp-Users"
>Cc: "Daniel K. O."
>Assunto: [Dev-C++] Re: 10 quick questions
>
>
>It looks like you need gtk+ and pw32 (a posix emulation layer)
>
>You can find them at:
>  Pw32:http://pw32.sourceforge.net/
>  Gtk+:http://gtk.org (dev-c++ packages at
>http://www.bloodshed.net/dev/packages/gtk.html)
>
>I think that these 2 packages would remove most (all?) the errors.  But, I
>haven't used either - just read some of their docs.
>
>Evan Hempel
>
>PS: I think that there also is a dev-c++ package for pw32
>
>
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