# `flow_macro` See also: [Code docs](http://andrewdavidmackenzie.github.io/flow/code/doc/flow_macro/index.html) Flow is an attribute macro to be used on the structure that provides an implementation for a function (by implementing the `FlowImpl` trait), so that when compiled for the `wasm32` target, code is inserted to help read the inputs, help form the outputs and allocate memory (`alloc`) as well as serialize and deserialize the data passed across the native/wasm boundary.