Re: Prevent wildcards from being accepted in filenames (NT mode)

[David Laight]

> According to the language definition, a constant 0 in
>       a pointer context is converted into a null pointer at
>       compile time.

Indeed even if the stored bit pattern for the 'NULL' pointer isn't
all zero [1], then the literal 0 denotates a NULL pointer.
So:
	char *p = 0;
	if (*(int *)&p != 0)
		printf(...);
can call printf.

It is also valid to '#define NULL (void *)0' that value is compatible
with function pointers - even though a function pointer can't be assigned
to a 'void *' variable.

	David

[1] I don't know of any such C implementation, but I some mainframe OS
have used the all 1 bit pattern for illegal pointers.

-- 
David Laight: david(a)l8s.co.uk