🚀 go-pugleaf

In article <GLENN.90Aug1145326@huxley.bitstream.com>,
glenn@bitstream.com (Glenn P. Parker) writes:
|> Until recently (after C++ invented it), C did not have "const".  Therein
|> lies some confusion.  I submit that it is absurd to put const in the same
|> category with other type names.  Const is not a typename, it is a storage
|> qualifier, like "auto" and "static".  You can't typecast from auto to
|> static, and I agree with Jim that you shouldn't be able to cast from const
|> to non-const.

The overloading system in C++ treats const as part of the type; there may be

int foo(char*);
int foo(const char*);

and these may be two different functions.  const is part of the type; it's
different from static and auto.

I've had to write casts from const to non-const because the following situation
sometimes arises:

a) The writer of some library function declares an argument to be type char*,
   although the string is not changed by the function;

b)  I want to pass a const char* to it.  I wouldn't want to see this forbidden.

I do think it's reasonable to give writers of optimizing compilers carte
blanche
to assume that a function that takes a pointer to const cannot under any
circumstances change the object.  If you cheat and do it anyway by casting
or other tricks, the compiler is free to break your code; you deserve to lose.

Historically (from C) a cast says "trust me, I know what I'm doing".  The same
should apply in C++.  The programmer should be allowed to write any type of
cast, and the resulting program may be non-portable if he does.


--
Joe Buck
jbuck@galileo.berkeley.edu	 {uunet,ucbvax}!galileo.berkeley.edu!jbuck