Trait ExternalArgs 

pub unsafe trait ExternalArgs {
    const FINGERPRINT: MethodFingerprint;
    const METADATA: &[u8];
}

Marker trait for external arguments when calling methods.

Safety

Struct that implements this trait must be #[repr(C)] and valid ExternalArgs for the contract method with Self::FINGERPRINT and Self::METADATA, since executors read it according to that metadata and some of them trust it without checking (like the native executor).

A call can leave contents behind in outputs that are not valid values of their types, even when it succeeds, and it only initializes the return value. Hence outputs must point to memory whose contents are not accessed afterward as values of their types without being parsed first, unless every bit pattern is a valid value. Memory from OutputArg::as_raw_output() is such memory while it stays exclusively borrowed for the lifetime of the struct. The return value must not be accessed as a value of its type without being parsed either.

Do not implement this trait explicitly! Implementation is automatically generated by the macro which generates contract implementation.

Required Associated Constants

const FINGERPRINT: MethodFingerprint

Fingerprint of the method being called

const METADATA: &[u8]

Metadata that corresponds to a method being called

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors