Attribute Macro interoptopus::ffi_function

#[ffi_function]

This is supported on crate feature derive only.

Enable an extern "C" function to appear in generated bindings.

This will derive FunctionInfo for a helper struct of the same name containing the function’s name, parameters and return value.

The following attributes can be provided:

Attribute	Explanation
surrogates(x="y")	Invoke function y to provide a CTypeInfo for parameter x, see below.

Surrogates

When dealing with types outside of your control you will not be able to implement CTypeInfo for them. Instead you need a surrogate, a helper function which returns that info for the type.

The surrogate’s signature is:

fn some_foreign_type() -> CType {
    // Return an appropriate CType
}

Example

use interoptopus::ffi_function;

#[ffi_function]
#[no_mangle]
pub extern "C" fn my_function(x: u32) -> u32 {
    x
}