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From: BostonU SysMgr <root%bostonu.csnet@csnet-relay.arpa>
Newsgroups: net.unix-wizards
Subject: 4.2::SYSV compatability problem
Message-ID: <7797@brl-tgr.ARPA>
Date: Tue, 29-Jan-85 03:40:17 EST
Article-I.D.: brl-tgr.7797
Posted: Tue Jan 29 03:40:17 1985
Date-Received: Sat, 2-Feb-85 13:51:42 EST
Sender: news@brl-tgr.ARPA
Organization: Ballistic Research Lab
Lines: 36


Apologies in advance if this has been resolved in the past or I am being
dense (although that means several people here got denseness problems):

Under 4.2bsd if, say, you have a foo.h file with a line like:

	int thing ;

and include it in a few .c files everything goes fine. In SYS5
(we are running SYS5.2 on a 3B5) you get 'multiply defined' errors.
Ok, not unexpected. I have in the past just changed such a file to
something like:

#ifdef MAIN
#define EXTERN
#else
#define EXTERN extern
#endif

EXTERN int thing ;

And defined MAIN in only one place (like where main() occurs.)

Problem: Suppose now you are faced with a program with about 40 .h files
and probably hundreds of such indiscretions. WORSE: many many typedefs
making something like 'g/int /s//EXTERN int /' (if I may speak ed in
mixed company) for each C type not enough.

What's a nurd to do? 'Fixing' SYS5 ld certainly comes to mind,
(apparently berkeley already took this course once) any other
suggestions welcome as it will be a few weeks before sources arrive and
I got things to get on with....

Tx in advance.

	-Barry Shein, Boston University