On Mon, 2007-10-29 at 11:57 +0000, Darryl Miles wrote: > This then leads into the question. Is a pointer allowed to be invalid.
A variable of type X need not contain an X in C, however the effect of any operation including assignment, copying, or passing is undefined if the value isn't valid. Valid pointers are NULL or a pointer to, into, or one past the end of any individual storage block. However most architectures/ABI's work fine copying invalid pointers. The rule is partly due to Intel segmented memory, allowing pointers to be passed in Segment:offset register pairs, which in protected mode requires a valid segment descriptor. -- John Skaller <skaller at users dot sf dot net> Felix, successor to C++: http://felix.sf.net
