[TUHS] origins of void*

Steve Johnson scj at yaccman.com
Mon Nov 6 14:59:45 AEST 2017

I tried to post this once, but it doesn't seem to have worked. 
 Apologies if you see this twice...



Ok, here's my memory of void *, blurred as it may be by time.

Void was put into C, but it was actually not necessary by itself --
the default return type was int, and if nobody was using the value
there was no particular reason to use void.  So only those who were
practitioners of the strong-type religion tended to use it.  A major
problem in making C strongly typed was deciding on a return type for
malloc.  It had traditionally returned char *, but this required a
cast to allow you to allocate things other than characters.

I was at a /usr/grp conference at the alcohol-fueled reception talking
to Charlie Roberts about the problems of making C more strongly
typed.  The topic of malloc came up.  All of a sudden Charlie got a
huge grin on his face and said "Hey!  Why don't we have malloc return
void *".   It took me a minute or two to even understand what void *
could possibly mean, but the idea was an instant winner.   I seem to
recall it was done a week or two later.   The idea may have simply
ready to be born and others may have had it as well, but this is what
I remember of it.  And the experience sticks in my mind as being an
almost literal example of being "struck by an idea".



----- Original Message -----
 "Doug McIlroy" <doug at cs.dartmouth.edu>

<tuhs at minnie.tuhs.org>

Sun, 05 Nov 2017 19:37:16 -0500
Re: [TUHS] origins of void*

 As has been explained, void came from Algol 68 via Steve Bourne.
 As no object could be declared void, void* was a useless
 construct. A kind of variable that could point to any object
 was required to state the type of useful functions like qsort.
 To avoid proliferation of keywords, the useless void* was
 pressed into service. I do not remember who suggested that.


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