Dennis Ritchie, RIP
Derek M. Jones
Dennis Ritchie, the inventor of C and author of
"The C programming language" died over the weekend.
Geoff Clare
I kept one of his posts to this group that tickled me.
Here it is for those who weren't around back then (1999) or
who don't remember it:
| From: Dennis Ritchie <dmr@.........>
| Newsgroups: comp.std.c
| Subject: Re: Integer Sizes?
| Date: Thu, 02 Dec 1999 03:19:41 +0000
|
| Someone (well, OK, Nick) wrote:
|
| > ... No, that is not the issue. You clearly have not thought of the
| > problem of handling external data formats, which was the rationale
| > for introducing the exact-width data types in the first place.
| >
| > A device driver or external file data object of 32 bits long will
| > contain those bits in a certain order. There is no requirement for
| > that to be the same order that is used by C...
| >
| > The matter of byte ordering is too well-known to go into details;
| > it is common for the external value 1 when loaded as a uint32_t
| > to be 16777216. I have used systems where both big-endian and
| > little-endian bit orders WITHIN A BYTE were possible....
|
| Maybe by the time of the C0X standard, things will be pinned
| down well enough that it will become possible actually to
| write a TCP/IP stack, or conceivably an entire operating
| system in C. One might even imagine that it runs on several
| different machine architectures. A hope for the new milennium.
|
| Dennis
--
Geoff Clare <net...@gclare.org.uk>
Keith Thompson
Something similar, posted here in 1998:
| > You are right. It was nice back in the days when things like
| >
| > #if (sizeof(int) == 8)
| >
| > actually worked (on some compilers).
|
| Must have been before my time.
|
| Dennis
--
Keith Thompson (The_Other_Keith) ks...@mib.org <http://www.ghoti.net/~kst>
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"
James Kuyper
A number of mainstream media web sites have this story by now, but I
found that many of the articles describe him as the original author of
the "hello, world" program. I've no personal knowledge of the truth of
this, but Wikipedia's article
<http://en.wikipedia.org/wiki/Hello,_world> credits Brian Kernighan. It
also shows a rather scary predecessor of that program, from a 1972
tutorial for B:
main( ) {
extrn a, b, c;
putchar(a); putchar(b); putchar(c); putchar('!*n');
}
a 'hell';
b 'o, w';
c 'orld';
I have several questions about this code.
The reliance upon implicit int is clear, at least to those of us who
started programing C well before the ANSI standard. Is 'extrn' a typo,
or was the keyword spelled differently in B? Was '*n' was a predecessor
to '\n'? Apparently initialization of a variable did not require an '='?
Character constants containing multiple characters are permitted even in
modern C, though the meaning is implementation-defined. What did they
mean in B?
In modern C, no matter what value is passed to putchar(), no more than a
single character would be written; the above code seems to be written
with the expectation that four putchar() calls would produce output
containing 14 characters (including the newline character). How did that
work?
Ben Bacarisse
> On 10/13/2011 07:51 AM, Derek M. Jones wrote:
>> All,
>>
>> Dennis Ritchie, the inventor of C and author of
>> "The C programming language" died over the weekend.
>>
>> http://www.theregister.co.uk/2011/10/13/dennis_ritchie/
>
> A number of mainstream media web sites have this story by now, but I
> found that many of the articles describe him as the original author of
> the "hello, world" program. I've no personal knowledge of the truth of
> this, but Wikipedia's article
> <http://en.wikipedia.org/wiki/Hello,_world> credits Brian Kernighan. It
> also shows a rather scary predecessor of that program, from a 1972
> tutorial for B:
>
> main( ) {
> extrn a, b, c;
> putchar(a); putchar(b); putchar(c); putchar('!*n');
> }
> a 'hell';
> b 'o, w';
> c 'orld';
>
> I have several questions about this code.
>
> The reliance upon implicit int is clear, at least to those of us who
> started programing C well before the ANSI standard.
B is (was?) typeless so there is no implicit int. Everything is a
machine word.
> Is 'extrn' a typo,
> or was the keyword spelled differently in B?
No, that's how it was spelt.
> Was '*n' was a predecessor
> to '\n'?
Yes. That comes directly from BCPL.
> Apparently initialization of a variable did not require an '='?
Yup. In fact = was not permitted in extrn initialisations.
> Character constants containing multiple characters are permitted even in
> modern C, though the meaning is implementation-defined. What did they
> mean in B?
They were reasonably well-defined. putchar('abcd'); had to print an 'a'
and then a 'b' and so on. The number of permitted characters in one
word obviously depended on the machine, and that determined how many
characters you can have in a character constant.
> In modern C, no matter what value is passed to putchar(), no more than a
> single character would be written; the above code seems to be written
> with the expectation that four putchar() calls would produce output
> containing 14 characters (including the newline character). How did that
> work?
putchar does not print zero bytes. The bytes are right-aligned, so the
call putchar('!*n'); is the same as putchar('*0*0!*n'); but putchar
always ignores zero bytes so you'd get the same output from
putchar('!*0*n*0'); for example. putchar also ignores ASCII EOT which
it used to terminate strings in B (EOT is written *e).
--
Ben.