I am a competent user of Ubuntu 8.04, competent in python but just starting to learn C++.
I want to start making GUIs using gtk. On my system the gtk header files,installed with the system are in /usr/include/gtk-2.0/gtk.

I've been attempting an extremely basic script to try to access the header files, like this:

#include <iostream>
using namespace std;
#include <gtk>
int main() {
cout << "DONE";
return 0;
}

When attempting to compile it, I've been using the -I flag to direct it to the gtk header files. However I get a long list of errors like this:

gtk/gtkwindow.h:218: error: ‘GtkWindow’ was not declared in this scope
gtk/gtkwindow.h:218: error: ‘window’ was not declared in this scope
gtk/gtkwindow.h:219: error: ‘gboolean’ was not declared in this scope
etc etc.

Is this a namespace issue? Can someone tell me how to go about including these gtk header files, or maybe point me to an existing web page somewhere which addresses the issue.

Thanks in advance,
cb.

C++ namespaces are stupid.
all includes should before any using statments

You have a path issue, not a namespace one (always look at the first error from the compiler).

The gtk libraries have lots of include and library directories (not just /usr/include/gtk2.0), so it is usually easier just to use pkg-config to generate these, eg:

If you are using the C++ wrappers for gtk, you can also use gtkmm-config, eg:

Namespaces shouldn't be causing problems here.. The first problem is that your include should be <gtk/gtk.h>, not just <gtk>. You should also use `pkg-config gtk+-2.0 --cflags` in CXXFLAGS and `pkg-config gtk+-2.0 --libs` in LDFLAGS. You are using at least a Makefile to build this, right?

I would personally avoid "using namespace std". It pollutes your global namespace with all the symbols from the standard library. A classic example is that if you try to name a counter with the rather reasonable "count", it'll clash with the std::count function.

Thanks. Problem solved using pkg-config.
CB.

This is wrong, #includes can appear after using statements. They can appear at any point in the file, however in some locations it may not make sense (such as within a function), but a #include is just a preprocessor directive which says expand the contents of this file here, so it is quite legitimate to have a #include contain some code and expand it at that point. Having said that this is not anything that I would encourage.

But in summary what this means is that #includes can appear after code, such as a class or function declaration. Occasionally it is necessary to include a #include after a class declaration to avoid circular references.

Indeed. I've used a macro-based trick to make it easy to dynamically load functions from shared objects. I've also heard of some code that uses perl to create a lookup table that's #included in the right spot. XPM files are also just C, so you can #include them right into an app.