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From: drw@culdev1.UUCP (Dale Worley)
Newsgroups: comp.lang.misc
Subject: call by address (was Re: compilers and linkers)
Message-ID: <1783@culdev1.UUCP>
Date: Tue, 24-Nov-87 17:18:41 EST
Article-I.D.: culdev1.1783
Posted: Tue Nov 24 17:18:41 1987
Date-Received: Sat, 28-Nov-87 05:25:50 EST
Organization: Cullinet Software, Westwood, MA, USA
Lines: 20

barmar@think.COM (Barry Margolin) writes:
| >If all parameters are truly passed by address, then the constant "3"
| >would be changed for I.EQ.1 and therefore the second invocation of
| >FUNC would return .FALSE.  
| 
| It doesn't have to do that.  It depends on what the "address" of a
| constant is.  Except for some early, buggy ones, most call-by-address
| implementations treat a literal parameter as an expression: [...]

The Fortran II language consistently treated constant arguments by
passing the address of the original constant.  Since all occurrances
of one constant value were treated the same, it made for some hard to
find bugs.  The language manual pointed out that using constants for
arguments that were assigned to was invalid.  They wised up when they
wrote Fortran IV.

Dale
-- 
Dale Worley    Cullinet Software      ARPA: culdev1!drw@eddie.mit.edu
UUCP: ...!seismo!harvard!mit-eddie!culdev1!drw
If you get fed twice a day, how bad can life be?