This is the mail archive of the mailing list for the GCC project.

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]

Re: ATTRIBUTE_WEAK (drift, but...)

I thought I'd wait until the primary focus of this discussion
had closed, which with Jeff's fixes, it appears to have done.

I could only sigh when I watched the rediscovery of a concept
that's been around for a very long time: that there are two
types of "weak" symbols.  The good folks (and it's well worth
looking at a lot of their work) at SDS (Scientific Data Systems)
later known as XDS (Xerox Data Systems) really understood their
business: they had good, solid, reliable solutions to this problem
(including the semantic confusion that "weak" causes) with
the concept of "secondary definition" and "secondary reference".
In fact, their object language was a real language and permitted
things (like the difference of two externals) that most so-called 
modern linkers can't handle (but which made for clean, elegant
assembler code).  (And a lot of other really nice solutions to problems
that continue to plague us, both in hardware design and software
design, even today.  They really thought the problems through.)

You'll notice I said "had".  I first got to know them in 1970,
but by 1976 or so, they were moribund.  Never did hear what
finally happened to them.  This is a piece of our past that
contains lessons for us that I wish more of us could see.  No,
they weren't perfect (and no, I wouldn't choose their OS
over Unix, but I'd sure like to see some concepts!), but it's
too bad that so much of what they did well has been lost
not only technically, but conceptually.  They were far ahead
of their time, and arguably ahead of our time in places.


P.S.  If you ever get a chance, and enjoy a good pun, read
their circa 1974 Fortran reference.  The only place I've ever
seen puns (and jokes) in a language referece that didn't
interfere with the readability of the document.  (But you
HAVE to be awake.)

Donn Terry        
Softway Systems, Inc.
2850 McClelland Dr, Ste. 1800   Ft.Collins CO 80525
Tel: +1-970-204-9900           Fax: +1-970-204-9951

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]