A proc attribute macro that sets the ABI/calling convention for the attributed function.
#[macro_use] extern crate fn_abi;
#[abi("fastcall")]
extern fn hello_world_fastcall() {
println!("hello world!");
}
#[cfg_attr(all(target_os = "windows", target_pointer_width = "32"), abi("thiscall"))]
#[cfg_attr(all(target_os = "windows", target_pointer_width = "64"), abi("fastcall"))]
extern fn hello_world_windows() {
println!("hello world!");
}