Function getpwnam_r 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn getpwnam_r(
    name: *const c_char,
    out: *mut passwd,
    buf: *mut c_char,
    size: size_t,
    result: *mut *mut passwd,
) -> c_int

See https://pubs.opengroup.org/onlinepubs/9799919799/functions/getpwnam.html.