Why NULL is 0
Dave Jones
djones at megatest.UUCP
Wed Apr 6 01:18:56 AEST 1988
in article <10229 at steinmetz.steinmetz.ge.com>, davidsen at steinmetz.steinmetz.ge.com (William E. Davidsen Jr) says:
>
> There has been a great deal of misunderstanding of the use of zero and
> pointers. It seems clear in K&R and practice that assignment of a zero
> to a pointer produces a NULL pointer of the appropriate type. What is
> incorrectly assumed is that zero *is* a NULL pointer.
>
... [ Lot's of good, true, stuff about pointers etc. ]
> There are many programs which "have worked for years" which are not
^^^^^ ^^^ ^^^^ ^^^^^^^^ ^^^^^ ^^^^ ^^^^^^ ^^^ ^^^^^ ^^^^^ ^^^ ^^^
> portable, because of this lack of typing on arguments. Most of these run
^^^^^^^^
> on any machine which has the size of int equal sizeof pointer, and all
> pointers are the same in content. This includes the VAX and 68000
> family. Other machines, such as some Data General models, Cray, small
> Intel processors, SPARC, and some non-UNIX C compilers on any machine
^^^^^
> will not accept this lack of explicit typing.
> --
> bill davidsen (wedu at ge-crd.arpa)
> {uunet | philabs | seismo}!steinmetz!crdos1!davidsen
> "Stupidity, like virtue, is its own reward" -me
SPARC? Really? REALLY?? What have they done? Please clarify.
This is news to me. I was naively assuming that since the current
class of Sun workstations is MC68020, they would attempt to be sure
that 68000 C programs would be portable to SPARC. (Even non-portable ones
which "have worked for years.")
I'm stunned. Really. REALLY!! Stunned.
Please tell me this was just an April Fool's joke that got here a
little late.
Dave (int*) Jones
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