rcs blows up on suns

[Antony Williams]

In article <151 at maynard.UUCP> campbell at maynard.UUCP (Larry Campbell) writes:
>A minor point, but dereferencing zero only "works" on Vaxen that are
>running Berkeley Unix (don't know about USG).  VMS sets page zero to
>no access; this is one of the few areas where I concede VMS a point
>over Unix.  It catches an all-too-common programming error.

This is a difficult decision for implementors:  the error is so common
that disabling address zero causes just about every Unix program to dump
core under some circumstance.  One instance I recall is that PIC
will dereference null pointers if given syntactically incorrect
input.  It works fine with correct input.  The problem with PIC
is exacerbated in that the null pointer is used as a pointer to
various kinds of structure, with further pointers at various
offsets:  V7 Unix on PDP11/70 used to ensure a few bytes of zeros
at address zero, but behaviour like that of PIC seems to require
an unknowable number of zeros to avoid the error.
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