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# Error code E0045

Variadic parameters have been used on a non-C ABI function.

Erroneous code example:

    #![allow(unused)]
    fn main() {
    extern "Rust" {
        fn foo(x: u8, ...); // error!
    }
    }

Rust only supports variadic parameters for interoperability with C code in its FFI. As such, variadic parameters can only be used with functions which are using the C ABI. To fix such code, put them in an extern "C" block:

    #![allow(unused)]
    fn main() {
    extern "C" {
        fn foo (x: u8, ...);
    }
    }