Re: Easily-Read C++?

[tmb@arolla.idiap.ch (Thomas M. Breuel)]

In article <CxoLLu.Av3@uunet!aadt> a311581@ventures.NoSubdomain.NoDomain (Kevin Cline) writes:
|In article <EMERY.94Oct12165432@goldfinger.mitre.org>, emery@goldfinger.mitre.org (David Emery) writes:
||> The ambiguity 'inherent' in declarations such as
||> 	char * foo;
||> 	char ** foo;
||> 	char foo[];
||> 	char *foo[];
||> causes problems for C tools.  Even though each of the above is
||> 'unambiguous', common usage means that any of these can be used to
||> represent the others.   At least one tool I know of (an RPC generator
||> for C) requires the user to disambiguate some of the above
||> declarations, to make sure that the tool generates the right code.
||> 
|These declarations are not equivalent.  The first is equivalent to the third,
|and the second to the fourth.
|
|The equivalence of C pointers and arrays is unfortunate.  It is maintained
|by C++ for backward compatibility reasons.  Most C++ applications use
|a library template array class instead of C arrays.

None of those declarations are equivalent (if people want to criticize
C, they should at least have a basic understanding of it!).

Furthermore, the problem that RPC systems have with C is that arrays
and pointers do not carry bounds information with them.  (Another
problem is that C pointers can point to heap data, into the middle of
other data structures, or to stack data.)

That is indeed a problem in some situations, but it is not related to
declaration syntax.  On the other hand, real-world users will probably
not accept a language that doesn't provide some equivalent of C's
plain arrays: the overhead of carrying bounds information around at
runtime is sometimes unacceptable.

In C++, none of this is a problem: arrays usually carry bounds
information (static or dynamic) and can easily be serialized for RPC.
C-style arrays need only be used in very specific situations.

				Thomas.