Macro get_libfn 

macro_rules! get_libfn {
    ($lib_path: expr, $fn_name: expr, $call_name: ident, $ret: ty, $($v: ident: $t:ty),*) => { ... };
    ($lib_path: expr, $fn_name: expr, $call_name:ident, $ret: ty) => { ... };
}

Get a function from a dynamic link library

You need use libloader::libloading first

• lib_path: the path of DLL
• fn_name: The function name from dll
• call_name: The call function name of fn_name
• ret: return type of the function if the function don’t have return value, use “()” instead
• (value: type): (variadic argument) The arguments of the function from dll

Example

get_libfn!("libstd.dylib", "println", my_println, (), str: &str);
my_println("Hello World");

get_libfn!("libstd.dylib", "add", my_add, usize, a: usize, b: usize);
println!("10 + 20 = {}", my_add(10, 20));

get_libfn!("libstd.dylib", "print_hello", my_print_hello, ());
my_print_hello();

the contents of libstd.dylib:

#[no_mangle]
pub fn println(str: &str) {
    println!("{}", str);
}
#[no_mangle]
pub fn add(a: usize, b: usize) -> usize {
    a + b
}
#[no_mangle]
pub fn print_hello() {
    println!("Hello");
}