Function callback_ret_string 

pub unsafe fn callback_ret_string(
    ptr: *mut u8,
    len: usize,
) -> Result<String, ForeignError>

Adopt a string a vtable entry wrote to its out_ptr/out_len slots.

Errors

Returns a MARSHAL_ERROR_CODE failure for a null pointer with a non-zero length or bytes that aren’t UTF-8.

Safety

Same contract as callback_ret_bytes.