Function do_openn 

pub unsafe fn do_openn(
    my_perl: *mut PerlInterpreter,
    a: *mut GV,
    b: *const c_char,
    c: I32,
    d: c_int,
    e: c_int,
    f: c_int,
    g: *mut PerlIO,
    h: *mut *mut SV,
    i: I32,
) -> bool

thx shim for crate::do_openn.