bsd_auth(3) question

[rustyBSD]

Hi,
is there a wayto useauth_userokay()without setgid
to "auth" ?

When testing this code:

#include <stdlib.h>
#include <login_cap.h>
#include <bsd_auth.h>
#include <stdio.h>
#include <stdlib.h>

int main()
{
    printf("authentication ");

    char *user = strdup("me");
    char *pass = strdup("pass");

    if (!auth_userokay(user, NULL, "auth-mytest", pass))
        printf("failed\n");
    else
        printf("successful\n");
    return 0;
}

I get:

$ ./test            
test: invalid script: /usr/libexec/auth/login_passwd
authentication failed

So it seems that I have to setgid to "auth", and my binary
must be setuid.

Am I wrong ? Is there a way of authenticatingwithout being
setuid ?

Thanks