Function do_open 

pub unsafe fn do_open(
    my_perl: *mut PerlInterpreter,
    g: *mut GV,
    n: *const c_char,
    l: I32,
    a: c_int,
    rm: c_int,
    rp: c_int,
    sf: *mut PerlIO,
) -> bool

thx shim for crate::do_open.