[TUHS] origins of void* -- Apology!

[Steve Johnson]

I had a senior moment when I sent out my posting about the origin of
void *.   The person in question
was Larry Rossler, not Charlie Roberts -- apologies to both!

Larry was active in the ANSI committee, so he had a bully pulpit for
suggesting this change...

About Bliss, there certainly was a bit of a competition for a while
between C and Bliss, and Bliss wasn't such a bad language.  But the
technology behind it was pretty ugly.  You had to compile PDP-11
programs on a Dec System 20, which shut out a large percentage of the
people who might have been interested.   And they took a very
relaxed stance of pointer aliasing -- basically, the compiler assumed
that no two pointers pointed to the same thing unless you turned on a
flag in which case it assume all pointers pointed to all other
pointers.  This would not have worked well for system code...

Pascal was a much more serious competitor -- it was much easier to
teach 75 people in a room how to program in Pascal than in C, and
P-code was a reasonable portability mechanism.  The differences have
been much discussed in this forum so I won't restart that thread
again...

At one point about 15 years after C has pretty much won over Bliss, I
gave a job interview to a programmer at Dec who was responsible for
maintaining 50 million lines of bliss.   I've rarely met anyone who
was more determined to change jobs!

Steve

----- Original Message -----
From:
 "Warner Losh" <imp at bsdimp.com>

To:
<arnold at skeeve.com>
Cc:
"TUHS main list" <tuhs at minnie.tuhs.org>, "Paul Ruizendaal"
<pnr at planet.nl>
Sent:
Mon, 6 Nov 2017 08:02:53 -0700
Subject:
Re: [TUHS] origins of void*

On Mon, Nov 6, 2017 at 12:24 AM, <arnold at skeeve.com [1]>
 wrote:
Paul Ruizendaal <pnr at planet.nl [2]> wrote:

 > >> In the 4BSD era there was caddr_t, which I think was used for
pretty
 > >> much the same purposes.
 > >
 > > Only for kernel code. I am pretty sure caddr_t wasn't used in
user-land code.
 >
 > Ah, thanks for pointing that out, I had not realised that and it
helps
 > explain some things. But why wasn’t caddr_t used for user-land
code:
 > usage in the signature of e.g. write() would have made sense,
right?

It's clear from K&R 1 that char* served as both pointer to string and
 generic pointer to memory.  That's not unreasonable, since, in some
sense,
 "memory is just bytes".  So user-land code didn't need caddr_t.  I
also
 suspect that caddr_t came into being with the effort to port Unix off
 the PDP-11 and the weight of Unix practice before then had been to
make
 do with char*.

 I think it helps to remember the evolutionary processes that were
happening
 in the '70s.  High level languages had caught on for application
code
 (FORTRAN and COBOL in the US, Algol in Europe) but the weight of
existing
 practice for *systems coding* (operating systems and utilities) had
been
 to use assembly language.  Multics proved that you could write an OS
in
 a high level language, but Multics itself (at that time) wasn't a
success.

 So when C came along in the mid-'70s, strong typing had essentially
been
 absent from systems programming.  With time and experience, along
with
 the recognition in the general CS world that strong typing was
valuable,
 C also started to evolve in that direction.

I thought there'd also been some influences from BLISS... DEC did much
of their system programming in BLISS along side the
MACRO-{11,32,20}....  Not exactly a strongly typed language, but
another entry in the higher level language category that C was
competing against.

Warner 

 

Links:
------
[1] mailto:arnold at skeeve.com
[2] mailto:pnr at planet.nl

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