"David Abrahams" <dave@boost-consulting.com> wrote
The provided example shows what registration needs to be done to calculate the type of a lambda functor:
#include BOOST_TYPEOF_BEGIN_REGISTRATION()
Where would that line go, in a header file?
BOOST_TYPEOF_REGISTER_TEMPLATE(tuples::tuple, 2); BOOST_TYPEOF_REGISTER_TEMPLATE(lambda_functor, 1); .... BOOST_TYPEOF_REGISTER_TYPE(placeholder<2>);
#include BOOST_TYPEOF_END_REGISTRATION()
Where would that line go, in a source file? If so, that sounds error-prone to me.
Everything would go into one file -- source or header. The BEGIN_REGISTRATION establishes a unique REGISTRATION_GROUP (using the counter suggested by Paul Mensonides). The REGISTRATION_GROUP is then used by the registration macros in conjunction with __LINE__ to generate unique integer identifiers. The END_REGISTRATION is technicaly not necessary. It just undefs the REGISTRATION_GROUP to force other files use the BEGIN_REGISTRATION (and so avoid potential clashes). Arkadiy