pub unsafe extern "C" fn x509_crt_verify(
    crt: *mut x509_crt,
    trust_ca: *mut x509_crt,
    ca_crl: *mut x509_crl,
    cn: *const c_char,
    flags: *mut u32,
    f_vrfy: Option<unsafe extern "C" fn(arg1: *mut c_void, arg2: *mut x509_crt, arg3: c_int, arg4: *mut u32) -> c_int>,
    p_vrfy: *mut c_void
) -> c_int