From: jnc@mercury.lcs.mit.edu (Noel Chiappa)
Subject: [TUHS] early cc variable and function names
Date: Thu, 16 Oct 2014 22:29:13 -0400 (EDT) [thread overview]
Message-ID: <20141017022913.7A77818C092@mercury.lcs.mit.edu> (raw)
> From: Mark Longridge <cubexyz at gmail.com>
> It seems like early cc could only use variable and function names up to
> 8 characters.
> This limitation occurs in v5, v6 and v7.
> ...
> That seems to suggest that only the first 7 characters are significant,
> but when looking at other sources they stated that one can use up to 8
> characters.
The a.out symbol tables use 8-character fields to hold symbol names. However,
C automagically and unavoidably prepends an _ to all externals (I forget
about automatics, registers, etc - too tired to check right now), making the
limit for C names 7 characters.
> I am not sure if limitations of early cc were documented anywhere.
I remember reading the above.
Other limits... well, you need to remember that C was still changing in that
period, so limits were a moving target.
> When I backported unirubik to v5 it compiled the longer functions
> without any problem.
ISTR that C truncated external names longer than 7 characters. Probably the
ones in that program were all unique within 7, so you won.
> Did anyone document these sorts of limitations of early cc?
I seem to recall at least one document from that period (I think pertaining
to the so-called 'Typesetter C') about 'changes to C'.
Also, I have started a note with a list of 'issues with C when you're
backporting V7 and later code to V6', I'll see if I can dig them out tomorrow.
Noel
next reply other threads:[~2014-10-17 2:29 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-17 2:29 Noel Chiappa [this message]
2014-10-17 2:40 ` John Cowan
2014-10-17 2:52 ` Larry McVoy
2014-10-17 3:46 ` John Cowan
2014-10-17 3:54 ` Larry McVoy
2014-10-17 19:41 ` Clem Cole
2014-10-17 20:37 ` random832
2014-10-17 20:42 ` Larry McVoy
-- strict thread matches above, loose matches on Subject: below --
2014-10-18 10:32 Noel Chiappa
2014-10-18 23:03 ` Ron Natalie
2014-10-18 23:11 ` Dave Horsfall
2014-10-17 16:11 Noel Chiappa
2014-10-17 1:51 Mark Longridge
2014-10-17 2:20 ` Milo Velimirovic
2014-10-17 2:21 ` Dave Horsfall
2014-10-17 13:35 ` random832
2014-10-17 13:44 ` Warner Losh
2014-10-17 14:07 ` arnold
2014-10-17 14:22 ` Milo Velimirović
2014-10-17 19:29 ` random832
2014-10-18 7:25 ` Greg 'groggy' Lehey
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