John Maddock ha escrito:
Joaquín Mª López Muñoz wrote:
If you only want the predicate for displaying purposes, maybe you can use something like this:
template<typename T,std::size_t Size> struct is_complete:boost::mpl::bool_<Size>{};
BOOST_MPL_ASSERT((is_complete<foo,sizeof(foo)>));
No that doesn't do it: you never get as far as the MPL error messages 'cos the sizeof(foo) fails to compile (this is what I'm using already to generate an error BTW).
Oh, certainly, you're right, applying sizeof() to an incomplete type is illegal, sorry for not thinking about it hard enough. Funny thing is that in GCC 3.2 sizeof() of an incomplete type evaluates to 0, so that struct foo; BOOST_MPL_ASSERT((is_complete<foo,sizeof(foo)>)); actually gets to the MPL error msg, yielding is_complete.cpp:11: `sizeof' applied to incomplete type `foo' is_complete.cpp:11: conversion from `mpl_::failed************is_complete<foo, 0>::************' to non-scalar type `mpl_::assert<false>' requested is_complete.cpp:11: enumerator value for `mpl_assertion_in_line_11' not integer constant Joaquín M López Muñoz Telefónica, Investigación y Desarrollo