3 Feb
2021
3 Feb
'21
5:47 a.m.
On Tue, Feb 02, 2021 at 03:08:42PM -0800, Greg A. Woods wrote:
At Sun, 20 Sep 2020 17:35:52 -0400, John Cowan
<cowan(a)ccil.org> wrote:
Subject: Re: [TUHS] reviving a bit of WWB
I've dealt with this, here is a story of a super computer where native
pointers pointed at bits but C pointers pointed at bytes and you can
shake your head at the promotion problems:
https://minnie.tuhs.org/pipermail/tuhs/2017-September/012050.html
When 0 is coerced implicitly or explicitly to a pointer type, it becomes a
null pointer. That's true even on architectures where all-bits-zero is
*not* a null pointer. However, in contexts where there is no expected
type, as in a call to execl(), the null at the end of the args list has to
be explicitly cast to (char *)0 or some other null pointer.
Yeah, that's more to do with the good/bad choice in C to do or not do
integer promotion in various situations, and to default parameter types
to 'int' unless they are, or are cast to, a wider type