2008-08-16  Sven Neumann  <sven@gimp.org>

	If a procedure call fails, pass a string describing the error as
	the second return value. First step towars fixing bug #344818.

	* app/pdb/gimpprocedure.[ch] (gimp_procedure_get_return_values):
	added a GError parameter. If it is set, pass the error message 
to
	the return values.

	* app/pdb/gimppdberror.h: added some more error codes.

	* app/pdb/gimppdb.c
	* app/xcf/xcf.c: pass errors to 
gimp_procedure_get_return_values().

	* app/plug-in/gimpplugin-message.c 
(gimp_plug_in_handle_proc_run):
	show a different error message for execution vs. calling errors.

	* app/plug-in/gimpplugin-progress.c
	(gimp_plug_in_progress_cancel_callback): pass the error
	GIMP_PDB_CANCELLED to gimp_procedure_get_return_values().

	* app/plug-in/gimppluginmanager-call.[ch]
	(gimp_plug_in_manager_call_run): removed the 
'destroy_return_vals'
	parameter.

	* app/plug-in/gimppluginprocedure.c: destroy the return values 
here.

	* app/plug-in/gimppluginprocframe.c: pass an error to
	gimp_procedure_get_return_values().

	* tools/pdbgen/app.pl
	* tools/pdbgen/pdb/fileops.pdb: generate code that passes the
	error to gimp_procedure_get_return_values().

	* app/pdb/*-cmds.c: regenerated.
	
	* plug-ins/pygimp/pygimp-pdb.c: extract the error message from 
the
	return values and pass it to the exception that is thrown.


svn path=/trunk/; revision=26593