main function has to implement wrong type.

[tbu-]

This is under the assumption that main should receive the same arguments and have the same return type as in C if it has the #[start] attribute:

Currently, the #[start] function has to have the type:

fn main(argc: isize, argv: *const *const u8) -> isize;

This is not an accurate translation of the C prototype, it has to be

fn main(argc: c_int, argv: *const *const u8) -> c_int;

And it's even wrong on x86_64, where isize = i64 and c_int = i32.

[huonw]

Dupe of #20064.

There's no particular reason that we have to match the C types, the Rust compiler just needs to e.g. create a shim function that does the appropriate casts (it's not like the return value of c_int is that correct anyway: e.g. POSIX systems only look at the lower byte).