#### allocator_binder::first_argument_type

The type of the function's first argument.

    typedef see_below first_argument_type;

The type of `first_argument_type` is based on the type `T` of the wrapper's target object:

- if `T` is a pointer to a function type accepting two arguments, `first_argument_type` is a synonym for the return type of `T`;
- if `T` is a class type with a member type `first_argument_type`, then `first_argument_type` is a synonym for `T::first_argument_type`;
- otherwise `first_argument_type` is not defined.

###### Requirements

Header: `asio/bind_allocator.hpp`

Convenience header: `asio.hpp`