[GRASS-dev] Error in previous declaration when compiling

[Glynn Clements]

rabotin wrote:

> It seems that grass/gis.h and the libgilbmm librarys declare a structure 
> with the same name: GModule.
> As I am steel a newbie in C and C++ developments, I don't really know 
> how to solve this problem.

It might work to use e.g.:

	#define GModule GRASS_GModule
	#include <grass/gis.h>
	#include <grass/Vect.h>
	#include <grass/dbmi.h>
	#include <grass/glocale.h>
	#undef GModule

You'll need to use GRASS_GModule when declaring the variable to hold
the pointer returned from G_define_module().

Note that you can't do it the other way around (change the name used
by glibmm) because type names are embedded in external symbols which
have C++ linkage.

I was going to suggest that gtkmm should be using C++ namespaces, but
it already does; GModule comes from glib itself.

I'm guessing that GRASS uses GModule because Module caused a conflict
sometime in the past (Flag and Option aren't called GFlag or GOption). 

The "G" prefix is a bit unfortunate really, given how many libraries
use it (usually from GNU; e.g. GNU Image Manipulation Program (GIMP)
-> GIMP ToolKit (GTK) -> gtk/gdk/glib -> gtkmm/glibmm).

-- 
Glynn Clements <glynn at gclements.plus.com>