GCC's statement expression extension

[Alexandre Oliva]

On Jul 29, 2000, Mark Mitchell <mark@codesourcery.com> wrote:

>   X x;
>   X f();
>   x = ({ f(); });

> Oops.  The return value of f() got destroyed before we got a chance to
> copy it.

I see.  We'd have to have copied it to some temporary that would hold
the result of the statement expression before calling its destructor.
But we'd have to special-case this copy to only be done for the last
statement of a statement-expression.  Too bad.

Maybe the way to go is to require statement expressions to contain
explicit `return' statements, at least in C++.  This would at least
make it easier to support them in C++.  Is `return' currently usable
within statement expressions?

-- 
Alexandre Oliva   Enjoy Guarana', see http://www.ic.unicamp.br/~oliva/
Red Hat GCC Developer                  aoliva@{cygnus.com, redhat.com}
CS PhD student at IC-Unicamp        oliva@{lsd.ic.unicamp.br, gnu.org}
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