✨ fn_has_this

A proc attribute macro that adds a this argument to a function.

This macro is well suited for conditional compilation. For example, some compilers will optimize away a this argument in a non-static function if it is unused, sometimes depending on calling convention. This macro makes it easy to conditionally compile your Rust programs to interact over FFI with functions compiled in this way.

Example

```rust

[macro_use]

extern crate fnhasthis;

use core::ffi::c_void;

[hasthis("*mut cvoid")] // Will create an argument called this in the function

pub unsafe extern "fastcall" fn print_pointer() { println!("{:x?}", this); }

[hasthis("me: *mut cvoid")] // You can also specify a custom name for the this argument

pub unsafe extern "thiscall" fn print_pointer() { println!("{:x?}", me); }

[cfgattr(targetos = "windows", hasthis("me: *mut cvoid"))] // Using cfg_attr, you can conditionally compile this attribute macro

pub unsafe extern "thiscall" fn print_pointer() { println!("{:x?}", me); } ```