my $string = priv_key($DH_private);

##</code><code>##

my $string = Crypt::DH::GMP::priv_key($DH_private);

##</code><code>##

char *
PerlCryptDHGMP_priv_key( PerlCryptDHGMP *dh )
{
    return PerlCryptDHGMP_mpz2sv_str(PerlCryptDHGMP_PRIVKEY_PTR(dh), 10, NULL);
}