Description

A |Trivial Metafunction| accepts a single argument of a class type x and returns the x's nested type member x::name, where name is a placeholder token for the actual member's name accessed by a specific metafunction's instance. By convention, all `trivial metafunctions`__ in MPL are named after the members they provide assess to. For instance, a |Trivial Metafunction| named first reaches for the x's nested member ::first.

Expression requirements

|In the following table...| name is placeholder token for the names of the |Trivial Metafunction| itself and the accessed member, and x is a class type such that x::name is a valid type-name.

Expression semantics

typedef name<x>::type r;

Models

• |first|
• |second|
• |base|

See also

|Metafunctions|, |Trivial Metafunctions|, |identity|