Function libperl_sys::PerlIO_openn

pub unsafe extern "C" fn PerlIO_openn(
    my_perl: *mut PerlInterpreter, 
    layers: *const c_char, 
    mode: *const c_char, 
    fd: c_int, 
    imode: c_int, 
    perm: c_int, 
    old: *mut PerlIO, 
    narg: c_int, 
    arg: *mut *mut SV
) -> *mut PerlIO