libloader 0.1.4

A easy-to-use dll loader for rust that based on libloading
Documentation 
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pub use libloading;

#[macro_export]
/// ## 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
/// ```rust
/// 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:
/// ```rust
/// #[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");
/// }
/// ```
macro_rules! get_libfn {
    ($lib_path: expr, $fn_name: expr, $call_name: ident, $ret: ty, $($v: ident: $t:ty),*) => {
        pub fn $call_name($($v: $t),*) -> $ret {
            unsafe {
                let lib = libloading::Library::new($lib_path).unwrap();
                let func: libloading::Symbol<fn($($t,)*) -> $ret> = lib.get($fn_name.as_bytes()).unwrap();
                func($($v,)*)
            }
        }
    };
    ($lib_path: expr, $fn_name: expr, $call_name:ident, $ret: ty) => {
        pub fn $call_name() -> $ret {
            unsafe {
                let lib = libloading::Library::new($lib_path).unwrap();
                let func: libloading::Symbol<fn() -> $ret> = lib.get($fn_name.as_bytes()).unwrap();
                func()
            }
        }
    };
}

#[cfg(test)]
mod tests {
    #[test]
    fn test_get_libfn() {
        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();
    }
}