Attribute which should never be encountered in real life.
This is something which features in the Rust source code generated
by autocxx-bindgen and passed to autocxx-engine, which should never
normally be compiled by rustc before it undergoes further processing.
Attribute to state that a Rust function is to be exported to C++
in the extern "Rust"
section of the generated cxx
bindings.
Attribute to state that a Rust type is to be exported to C++
in the extern "Rust"
section of the generated cxx
bindings.
Attribute to state that a Rust struct
is a C++ subclass.
This adds an additional field to the struct which autocxx uses to
track a C++ instantiation of this Rust subclass.