OpenSSL::PKey::PKey#initialize_copy

HAVE_EVP_PKEY_DUP
static VALUE
ossl_pkey_initialize_copy(VALUE self, VALUE other)
{
    EVP_PKEY *pkey, *pkey_other;

    TypedData_Get_Struct(self, EVP_PKEY, &ossl_evp_pkey_type, pkey);
    TypedData_Get_Struct(other, EVP_PKEY, &ossl_evp_pkey_type, pkey_other);
    if (pkey)
        rb_raise(rb_eTypeError, "pkey already initialized");
    if (pkey_other) {
        pkey = EVP_PKEY_dup(pkey_other);
        if (!pkey)
            ossl_raise(ePKeyError, "EVP_PKEY_dup");
        RTYPEDDATA_DATA(self) = pkey;
    }
    return self;
}