When building API programs, ensure that the include path for the compiler includes the path (in the CFLAGS variable):

-I$(ALIAS_LOCATION)/ODS/Common/include

where $(ALIAS_LOCATION) is usually c:\Program Files\Autodesk\Alias2012 (Windows) or /Applications/Autodesk/Alias2012/Alias.app/Contents/Resources (Mac).

On Windows, the CFLAGS and CPLUSPLUSFLAGS variable would include the following:

/I$(ALIAS_LOCATION)\ODS\Common\include