six-character extern id limit

[William E. Davidsen Jr]

In article <4003 at bsu-cs.UUCP> dhesi at bsu-cs.UUCP (Rahul Dhesi) writes:
| I said that I thought Doug Gwyn exaggerated in saying that "many" C
| implementors were not in a position to improve the linker that would
| "of necessity" be used with the output from their compiler.  The
| context was a discussion of ANSI's guaranteeing no more than 6
| significant characters in external names.
| 
| Both Doug Gwyn and Henry Spencer disagree.  But although I have been
| following this newsgroup for some time, I don't recall any specific
| cases being described of linkers that can't handle more than
| 6-character externals and that will of necessity be used to link C
| code.  Are there more than just a few?  (Remember, we're talking about
| a 6-character limit, not 7 or 8, which are more common.)

  The key here is politics and technology. Almost all of the 36 bit
machines use six char BCD names for at least some of their linkers. The
consensus was to make 31 char cases sensitive a "future direction" to
avoid any opposition from vendors who would have to write new linkers
for their C. Single case is even more prevalent, the IBM hack tell me
that most IBM systems still use it, even in EBCDIC.

  This is really a valid compromise. If a vendor is faced with either
spending a lot of money on an operating system or having competitors
saying stuff like "we have full ANSI C and {so-and-so} only has a
subset, we felt that vendors might either ignore C or actually oppose
it. To do something which might be seen as giving one vendor a marketing
advantage over another is not appropriate for the standard, since the
intent was to "codify current practice."

  Hopefully in C96 we will be able to start with a premise of "codifying
widely used extensions" or something. Being on a standards committee is
an educational experience, and I feel that I learned a lot from it.
-- 
	bill davidsen		(wedu at ge-crd.arpa)
  {uunet | philabs}!steinmetz!crdos1!davidsen
"Stupidity, like virtue, is its own reward" -me