NULL pointer dereferencing and printf
Martin Minow
minow at decvax.UUCP
Fri Jan 27 12:45:24 AEST 1984
This discussion seems to pop up once a year -- perhaps it could
be put in net.announce and be done with. You shouldn't dereference
NULL.
But people do -- mostly by accident. As a slight debugging aid,
the Decus C printf (and, I think, the V6 printf) test for
printf("%s", NULL) and print "{null}". This at least keeps
the bug from being fatal. Vax-11 C crashes the program which
gets the bug out quicker, I suppose.
(Actually, on Vax, the first 512 bytes of the user
address space can't be referenced, so most instances
of ((struct foo *) NULL)->bar are caught, too.
Martin Minow
decvax!minow
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