Re: [PATCH v1 19/25] man/man3type/void.3type: HISTORY: Update first POSIX appearance of void(3type)

[Adam Sampson <ats@offog.org>]

Alejandro Colomar <alx@kernel.org> writes:

> I think 'void*' is important enough that it would be useful to dig in
> its history further.  Was it an invention of C89?  Or was it an
> extension in some existing compilers?  If the latter, it would be
> interesting to document which systems had it before C89.

From evidence in the utzoo Usenet archive, the idea was around before
the ANSI C effort.

The first mention of "void *" is in November 1982, where Ken Dalka
(ihuxe!dalka) observed in net.lang.c that void * was accepted as a type.
He didn't say which compiler was being used, but an earlier post said
ihuxe "runs USG 4.0 UN*X".

The next is from Mary Ann Horton (mark@cbosgd.UUCP) in January 1984,
also in net.lang.c, who suggests using "(void *) 0" as a definition of
NULL, giving a varargs function with args terminated by NULL as an
example.

Then in March 1984, Doug Gwyn (gwyn@Brl-Vld.ARPA) says, as part of a
discussion about casting the result of malloc in net.unix-wizards:

> The C Language Standards Committee was talking about adding
> (void *) to the language as a generic pointer type.  Perhaps
> that will eventually help...

It then shows up in various posts in both of those groups throughout
1984, including a summary by Henry Spencer in June 1984 of Larry
Rosler's presentation on the ANSI C project at Usenix saying:

> II.  "void *" is a new kind of pointer, which cannot be dereferenced but
> 	can be assigned to any other type of pointer without a cast.  The
> 	idea here is that "char *" is no longer required to be the
> 	"universal" pointer type which can point to anything.  So for
>	example, the declaration of fread earlier really should go:
>
>		extern int fread(void *, int, int, FILE *);
>
>	(People who have machines where all pointers have the same
>	representation, don't complain.  You are lucky.  Others aren't.)

Thanks,

-- 
Adam Sampson <ats@offog.org>                         <http://offog.org/>