Re: Problem with 'import' directive

[Pascal Bourguignon]

Nicola Pero writes:
> If you think it's a compiler bug (it looks like) please submit the bug to
> the GCC bug tracking system at
> 
> http://gcc.gnu.org/cgi-bin/gnatsweb.pl
> 
> [It might not get fixed soon, but at least it's recorded, and someone
> will hopefully fix at some point.]
> 
> > I have problem with #import directive on my Linux Red Hat 7.2 machine (gstep
> > 0.8.0, gcc3)
> > 
> > My application has the following structure
> > 
> > A.subproj contains files: A1, A2, ...
> > B.subproj contains files: B1, B2, ...
> > 
> > A1 file has import:
> > ...
> > #import "A2"
> > ...
> > 
> > A2 file has import:
> > ...
> > #import "../B.subproj/B1"
> > ...
> > 
> > B1 file has import:
> > ...
> > #import "../A.subproj/A2"
> > ...
> > 
> > Compilation of this project terminate with error:
> > ... duplicated declaration of  ... (list of some symbols from A2 file)
> > 
> > I think, that compilator consider importing of files: "A2" and
> > "../A.subproj/A2" as two different files.
> > (On Solaris 8, or Openstep for Mach systems this problem does not appear)
> > 
> > Is there some solution for this problem ?
> 
> As a last resort ... using #include and include guards ? ;-)

Indeed, that's a typical case where #import does not work and why it's
discouraged/deprecated.  Use #include.

On the other hand, either with  #include if you insist to use #import,
I've found much  less problems when writing only the  file name in the
#include  or #import  directive and  dealing  with paths  only on  the
compiler command line argument with lists of -I.  

In the makefiles of the B.subproj, I would have: 
INCLUDES=-I. -I../A.subproj

while in the makefiles of the A.subproj, I would have:
INCLUDES-I. -I../B.subproj

The -I. being  before the other -I options because  if there are files
with  the same  name  in several  packages,  the local  one must  take
precedence.  By the same token, if  a package C is a subpackage of the
package B, then it should appear before in the INCLUDES list.


-- 
__Pascal_Bourguignon__                   http://www.informatimago.com/
----------------------------------------------------------------------
There is a fault in reality. Do not adjust your minds. -- Salman Rushdie