> In the case of an error in the main function, the process will exit with 1, otherwise 0. The main function can also return a value directly (return type u8 / !u8).

We know that by convention, but how do we know that from

    pub fn main() !void {

If if write

    pub fn foo() !void {

will that function also get to return a u8?

Also, what happened to argv/argc?