外部函数

extern "C" 块

通过 extern "C" 声明 C ABI 函数：

vix

extern "C"
{
    fn printf(format: ptr, ...): i32
    fn malloc(size: usize): ptr
    fn free(ptr: ptr): void
    fn strlen(s: ptr): usize
}

使用 ... 声明可变参数：

vix

extern "C"
{
    fn printf(format: ptr, ...): i32
    fn fprintf(file: ptr, format: ptr, ...): i32
}

vix

fn main(): i32
{
    let msg = "Hello from C!\n"
    printf(msg)
    return 0
}