Re: Why is not more FreeBSD software written in C++?

Don Dugger <dugger@hotlz.com> writes:
> Dag-Erling Sm=F8rgrav <des@des.no> writes:
> > Don Dugger <dugger@hotlz.com> writes:
> > > The fact is that all your c code will compile in c++
> > That is wrong.  To name just one example, C++ is much stricter about
> > type casts than C is.
> I mean the constructs. Casting will not change the functionality or
> shouldn't.

It does.  Casting can be (and often is) used to force or avoid sign
promotion in function arguments; for instance, isspace(ch) may produce
incorrect results if ch is a char, so a cast to int is required.

C allows any expression of pointer type to be assigned to a void *,
and allows any expression of type void * to be assigned to any object
pointer type.  C++ does not.  As a result, a typical C program which
uses malloc() without casting the result will not compile cleanly with
a C++ compiler.  A competent C programmer will balk at adding the cast
that C++ requires; a competent C++ programmer will correctly point out
that a C++ program should not use malloc() anyway.

There are other incompatiblities: const has different semantics in C
and C++, namespaces aren't quite the same (there is no separation
between the typedef namespace and the struct namespace in C++), etc.

DES
--=20
Dag-Erling Sm=F8rgrav - des@des.no
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