const comparison in C and C++

[T. William Wells]

In article <8516 at smoke.ARPA> gwyn at brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>) writes:
: C "const" basically constrains the means of access, so that for example
:       void copy(const char *source, char *destination, unsigned count);
: is a useful declaration for a function that is guaranteed not to alter
: storage via its first parameter.  However, assuming this represents a
: block-move function, the destination range is allowed to overlap the
: source range, because modification of any storage validly accessible via
: the second parameter is NOT prohibited.

Sorry Doug, it's undefined.  (And, drat, I get to fix a, guess
what, COPY FUNCTION, where I made this same mistake.  :-)

>From section 3.5.3:

"If an attempt is made to modify an object defined with a
const-qualified type through use of an lvalue with
non-const-qualified type, the behavior is undefined."

---
Bill
novavax!proxftl!bill