diff --git a/bin/main-c.c b/bin/main-c.c
index bc9a7e1..036c7c3 100644
--- a/bin/main-c.c
+++ b/bin/main-c.c
@@ -452,232 +452,26 @@ static int handle_logopt (hcl_client_t* client, const hcl_bch_t* str)
 
 /* ========================================================================= */
 
-struct proto_xtn_t
-{
-	int x;
-};
-typedef struct proto_xtn_t proto_xtn_t;
-
-static int handle_packet (hcl_xproto_t* proto, hcl_xpkt_type_t type, const void* data, hcl_oow_t len)
+static int client_on_packet (hcl_xproto_t* proto, hcl_xpkt_type_t type, const void* data, hcl_oow_t len)
 {
 	if (type == HCL_XPKT_STDOUT)
 	{
 		/*if (len > 0) fwrite (data, 1, len, stdout); */
 		if (len > 0) fprintf (stdout, "%.*s", (int)len, data);
 	}
+	else if (type == HCL_XPKT_STDERR)
+	{
+		if (len > 0) fprintf (stderr, "%.*s", (int)len, data);
+	}
+	else if (type == HCL_XPKT_ERROR)
+	{
+		/* error notification */
+		if (len > 0) fprintf (stderr, "ERROR: %.*s\n", (int)len, data);
+	}
 	return 1;
 }
 
-static int handle_request (hcl_client_t* client, const char* ipaddr, const char* script, int reuse_addr, int shut_wr_after_req)
-{
-	hcl_sckaddr_t sckaddr;
-	hcl_scklen_t scklen;
-	int sckfam;
-	int sck = -1;
-
-	hcl_oow_t used, avail;
-	int x;
-	hcl_bch_t buf[256];
-	ssize_t n;
-	const char* scptr;
-	const char* sccur;
-	hcl_xproto_t* proto = HCL_NULL;
-
-	client_xtn_t* client_xtn;
-	proto_xtn_t* proto_xtn;
-	hcl_xproto_cb_t proto_cb;
-
-	client_xtn = hcl_client_getxtn(client);
-
-	sckfam = hcl_bchars_to_sckaddr(ipaddr, strlen(ipaddr), &sckaddr, &scklen);
-	if (sckfam <= -1)
-	{
-		fprintf (stderr, "cannot convert ip address - %s\n", ipaddr);
-		goto oops;
-	}
-
-	sck = socket(sckfam, SOCK_STREAM, 0);
-	if (sck <= -1)
-	{
-		fprintf (stderr, "cannot create a socket for %s - %s\n", ipaddr, strerror(errno));
-		goto oops;
-	}
-
-	if (reuse_addr)
-	{
-		if (sckfam == AF_INET)
-		{
-			struct sockaddr_in anyaddr;
-			int opt = 1;
-			setsockopt(sck, SOL_SOCKET, SO_REUSEADDR, (char *)&opt, sizeof(opt));
-			memset (&anyaddr, 0, HCL_SIZEOF(anyaddr));
-			anyaddr.sin_family = sckfam;
-			bind(sck, (struct sockaddr *)&anyaddr, scklen);
-		}
-		else if (sckfam == AF_INET6)
-		{
-			struct sockaddr_in6 anyaddr;
-			int opt = 1;
-			setsockopt(sck, SOL_SOCKET, SO_REUSEADDR, (char *)&opt, sizeof(opt));
-			memset (&anyaddr, 0, HCL_SIZEOF(anyaddr));
-			anyaddr.sin6_family = sckfam;
-			bind(sck, (struct sockaddr *)&anyaddr, scklen);
-		}
-	}
-
-	if (connect(sck, (struct sockaddr*)&sckaddr, scklen) <= -1)
-	{
-		fprintf (stderr, "cannot connect to %s - %s\n", ipaddr, strerror(errno));
-		goto oops;
-	}
-
-	memset (&proto, 0, HCL_SIZEOF(proto_cb));
-	proto_cb.on_packet = handle_packet;
-
-	proto = hcl_xproto_open(hcl_client_getmmgr(client), &proto_cb, HCL_SIZEOF(*proto_xtn));
-	if (HCL_UNLIKELY(!proto))
-	{
-		fprintf (stderr, "cannot open protocol to %s\n", ipaddr);
-		goto oops;
-	}
-	proto_xtn = hcl_xproto_getxtn(proto);
-	//proto_xtn->client = client;
-
-	scptr = sccur = script;
-	while (1)
-	{
-		struct pollfd pfd;
-
-		pfd.fd = sck;
-		pfd.events = POLLIN;
-		if (*sccur != '\0') pfd.events |= POLLOUT;
-		pfd.revents = 0;
-
-		n = poll(&pfd, 1, 1000);
-		if (n <= -1)
-		{
-			fprintf (stderr, "poll error on %d - %s\n", sck, strerror(n));
-			goto oops;
-		}
-
-		if (n == 0)
-		{
-			/* TODO: proper timeout handling */
-			continue;
-		}
-
-		if (pfd.revents & POLLERR)
-		{
-			fprintf (stderr, "error condition detected on %d\n", sck);
-			goto oops;
-		}
-
-		if (pfd.revents & POLLOUT)
-		{
-			hcl_xpkt_hdr_t hdr;
-			struct iovec iov[2];
-			hcl_uint16_t seglen;
-
-			while (*sccur != '\0' && sccur - scptr < HCL_XPKT_MAX_PLD_LEN) sccur++;
-
-			seglen = sccur - scptr;
-
-			hdr.id = 1; /* TODO: */
-			hdr.type = HCL_XPKT_CODE | (((seglen >> 8) & 0x0F) << 4);
-			hdr.len = seglen & 0xFF;
-
-			iov[0].iov_base = &hdr;
-			iov[0].iov_len = HCL_SIZEOF(hdr);
-			iov[1].iov_base = scptr;
-			iov[1].iov_len = seglen;
-
-			hcl_sys_send_iov (sck, iov, 2); /* TODO: error check */
-
-			scptr = sccur;
-
-			if (*sccur == '\0')
-			{
-				hdr.id = 1; /* TODO: */
-				hdr.type = HCL_XPKT_EXECUTE;
-				hdr.len = 0;
-
-				iov[0].iov_base = &hdr;
-				iov[0].iov_len = HCL_SIZEOF(hdr);
-				hcl_sys_send_iov (sck, iov, 1);
-
-				if (shut_wr_after_req)
-				{
-					shutdown (sck, SHUT_WR);
-				}
-				else
-				{
-					hdr.type = HCL_XPKT_DISCONNECT;
-					hdr.id = 1; /* TODO: */
-					hdr.len = 0;
-
-					iov[0].iov_base = &hdr;
-					iov[0].iov_len = HCL_SIZEOF(hdr);
-					hcl_sys_send_iov (sck, iov, 1);
-				}
-			}
-		}
-
-		if (pfd.revents & POLLIN)
-		{
-			hcl_oow_t bcap;
-			hcl_uint8_t* bptr;
-
-			bptr = hcl_xproto_getbuf(proto, &bcap);;
-			x = recv(sck, bptr, bcap, 0);
-			if (x <= -1)
-			{
-				if (errno == EINTR) goto carry_on; /* didn't read read */
-				/*hcl_seterrwithsyserr (hcl, 0, errno); */
-				/* TODO: error info set... */
-				return -1;
-			}
-			if (x == 0) hcl_xproto_seteof(proto, 1);
-			hcl_xproto_advbuf (proto, x);
-		}
-
-
-	carry_on:
-		while (hcl_xproto_ready(proto))
-		{
-			if ((n = hcl_xproto_process(proto)) <= -1)
-			{
-				/* TODO: proper error message */
-				return -1;
-			}
-			if (n == 0)
-			{
-				/* TODO: chceck if there is remaining data in the buffer...?? */
-				printf ("NO MORE DATA. EXITING...\n");
-				goto done;
-			}
-		}
-
-		if (hcl_xproto_geteof(proto)) break;
-	}
-done:
-
-/* TODO: we can check if the buffer has all been consumed. if not, there is trailing garbage.. */
-	/*{
-		struct linger linger;
-		linger.l_onoff = 1;
-		linger.l_linger = 0;
-		setsockopt (sck, SOL_SOCKET, SO_LINGER, (char *) &linger, sizeof(linger));
-	}*/
-
-	hcl_xproto_close (proto);
-	close (sck);
-	return 0;
-
-oops:
-	if (proto) hcl_xproto_close (proto);
-	if (sck >= 0) close (sck);
-	return -1;
-}
+/* ========================================================================= */
 
 int main (int argc, char* argv[])
 {
@@ -753,6 +547,7 @@ int main (int argc, char* argv[])
 
 	memset (&client_prim, 0, HCL_SIZEOF(client_prim));
 	client_prim.log_write = log_write;
+	client_prim.on_packet = client_on_packet;
 
 	client = hcl_client_open(&sys_mmgr, HCL_SIZEOF(client_xtn_t), &client_prim, HCL_NULL);
 	if (!client)
@@ -779,16 +574,12 @@ int main (int argc, char* argv[])
 	set_signal (SIGINT, handle_sigint);
 	set_signal_to_ignore (SIGPIPE);
 
-#if 0
-	n = hcl_client_connect(client, argv[opt.ind], reuse_addr);
+	n = hcl_client_start(client, argv[opt.ind], argv[opt.ind + 1], reuse_addr, shut_wr_after_req);
 	if (n <= -1)
 	{
 		fprintf (stderr, "ERROR: %s\n", hcl_client_geterrbmsg(client));
 		goto oops;
 	}
-#else
-	n = handle_request(client, argv[opt.ind], argv[opt.ind + 1], reuse_addr, shut_wr_after_req);
-#endif
 
 	set_signal_to_default (SIGINT);
 	set_signal_to_default (SIGPIPE);
diff --git a/lib/hcl-x.h b/lib/hcl-x.h
index 48e4ea4..e2b2736 100644
--- a/lib/hcl-x.h
+++ b/lib/hcl-x.h
@@ -63,8 +63,8 @@ typedef struct hcl_xpkt_hdr_t hcl_xpkt_hdr_t;
 
 #define HCL_XPKT_HDR_LEN (HCL_SIZEOF(hcl_xpkt_hdr_t))
 
-/* the actual length field is 12 bits long. so the maximum payload length allowed per packet is 2^12 */
-#define HCL_XPKT_MAX_PLD_LEN (4096)
+/* the actual length field is 12 bits long. so the maximum payload length allowed per packet is 2^12 - 1 */
+#define HCL_XPKT_MAX_PLD_LEN (4095)
 
 /* ---------------------------------------------------------------------- */
 
@@ -162,12 +162,21 @@ typedef void (*hcl_client_log_write_t) (
 	hcl_oow_t         len
 );
 
+typedef int (*hcl_client_on_packet_t) (
+	hcl_xproto_t*   proto,
+	hcl_xpkt_type_t type,
+	const void*     data,
+	hcl_oow_t       len
+);
+
 struct hcl_client_prim_t
 {
 	hcl_client_log_write_t     log_write;
+	hcl_client_on_packet_t     on_packet;
 };
 typedef struct hcl_client_prim_t hcl_client_prim_t;
 
+
 /* ---------------------------------------------------------------------- */
 
 #if defined(__cplusplus)
@@ -306,10 +315,12 @@ HCL_EXPORT void hcl_client_close (
 	hcl_client_t* client
 );
 
-HCL_EXPORT int hcl_client_connnect (
+HCL_EXPORT int hcl_client_start (
 	hcl_client_t* client,
-	const char*   ptr,
-	int           reuse_addr
+	const char*   ipaddr,
+	const char*   script,
+	int           reuse_addr,
+	int           shut_wr_after_req
 );
 
 HCL_EXPORT int hcl_client_setoption (
diff --git a/lib/x-client.c b/lib/x-client.c
index 2d573b3..f4c80f2 100644
--- a/lib/x-client.c
+++ b/lib/x-client.c
@@ -388,169 +388,7 @@ struct proto_xtn_t
 };
 typedef struct proto_xtn_t proto_xtn_t;
 
-static int handle_packet (hcl_xproto_t* proto, hcl_xpkt_type_t type, const void* data, hcl_oow_t len)
-{
-	if (type == HCL_XPKT_STDOUT)
-	{
-		/*if (len > 0) fwrite (data, 1, len, stdout); */
-		if (len > 0) fprintf (stdout, "%.*s", (int)len, data);
-	}
-	return 1;
-}
-
-#if 0
-
-int hcl_client_process (hcl_client_t* client, const char* ipaddr, const char* script, int reuse_addr, int shut_wr_after_req)
-{
-	hcl_oow_t used, avail;
-	int x;
-	hcl_bch_t buf[256];
-	ssize_t n;
-	const char* scptr;
-	const char* sccur;
-	hcl_xproto_t* proto = HCL_NULL;
-
-	proto_xtn_t* proto_xtn;
-	hcl_xproto_cb_t proto_cb;
-
-	scptr = sccur = script;
-	while (1)
-	{
-		struct pollfd pfd;
-
-		pfd.fd = sck;
-		pfd.events = POLLIN;
-		if (*sccur != '\0') pfd.events |= POLLOUT;
-		pfd.revents = 0;
-
-		n = poll(&pfd, 1, 1000);
-		if (n <= -1)
-		{
-			fprintf (stderr, "poll error on %d - %s\n", sck, strerror(n));
-			goto oops;
-		}
-
-		if (n == 0)
-		{
-			/* TODO: proper timeout handling */
-			continue;
-		}
-
-		if (pfd.revents & POLLERR)
-		{
-			fprintf (stderr, "error condition detected on %d\n", sck);
-			goto oops;
-		}
-
-		if (pfd.revents & POLLOUT)
-		{
-			hcl_xpkt_hdr_t hdr;
-			struct iovec iov[2];
-			hcl_uint16_t seglen;
-
-			while (*sccur != '\0' && sccur - scptr < HCL_XPKT_MAX_PLD_LEN) sccur++;
-
-			seglen = sccur - scptr;
-
-			hdr.id = 1; /* TODO: */
-			hdr.type = HCL_XPKT_CODE | (((seglen >> 8) & 0x0F) << 4);
-			hdr.len = seglen & 0xFF;
-
-			iov[0].iov_base = &hdr;
-			iov[0].iov_len = HCL_SIZEOF(hdr);
-			iov[1].iov_base = scptr;
-			iov[1].iov_len = seglen;
-
-			hcl_sys_send_iov (sck, iov, 2); /* TODO: error check */
-
-			scptr = sccur;
-
-			if (*sccur == '\0')
-			{
-				hdr.id = 1; /* TODO: */
-				hdr.type = HCL_XPKT_EXECUTE;
-				hdr.len = 0;
-
-				iov[0].iov_base = &hdr;
-				iov[0].iov_len = HCL_SIZEOF(hdr);
-				hcl_sys_send_iov (sck, iov, 1);
-
-				if (shut_wr_after_req)
-				{
-					shutdown (sck, SHUT_WR);
-				}
-				else
-				{
-					hdr.type = HCL_XPKT_DISCONNECT;
-					hdr.id = 1; /* TODO: */
-					hdr.len = 0;
-
-					iov[0].iov_base = &hdr;
-					iov[0].iov_len = HCL_SIZEOF(hdr);
-					hcl_sys_send_iov (sck, iov, 1);
-				}
-			}
-		}
-
-		if (pfd.revents & POLLIN)
-		{
-			hcl_oow_t bcap;
-			hcl_uint8_t* bptr;
-
-			bptr = hcl_xproto_getbuf(proto, &bcap);;
-			x = recv(sck, bptr, bcap, 0);
-			if (x <= -1)
-			{
-				if (errno == EINTR) goto carry_on; /* didn't read read */
-				/*hcl_seterrwithsyserr (hcl, 0, errno); */
-				/* TODO: error info set... */
-				return -1;
-			}
-			if (x == 0) hcl_xproto_seteof(proto, 1);
-			hcl_xproto_advbuf (proto, x);
-		}
-
-
-	carry_on:
-		while (hcl_xproto_ready(proto))
-		{
-			if ((n = hcl_xproto_process(proto)) <= -1)
-			{
-				/* TODO: proper error message */
-				return -1;
-			}
-			if (n == 0)
-			{
-				/* TODO: chceck if there is remaining data in the buffer...?? */
-				printf ("NO MORE DATA. EXITING...\n");
-				goto done;
-			}
-		}
-
-		if (hcl_xproto_geteof(proto)) break;
-	}
-done:
-
-/* TODO: we can check if the buffer has all been consumed. if not, there is trailing garbage.. */
-	/*{
-		struct linger linger;
-		linger.l_onoff = 1;
-		linger.l_linger = 0;
-		setsockopt (sck, SOL_SOCKET, SO_LINGER, (char *) &linger, sizeof(linger));
-	}*/
-
-	hcl_xproto_close (proto);
-	close (sck);
-	return 0;
-
-oops:
-	if (proto) hcl_xproto_close (proto);
-	if (sck >= 0) close (sck);
-	return -1;
-}
-#endif
-
-int hcl_client_connect (hcl_client_t* client, const char* ipaddr, int reuse_addr)
+static int client_connect (hcl_client_t* client, const char* ipaddr, int reuse_addr)
 {
 	hcl_sckaddr_t sckaddr;
 	hcl_scklen_t scklen;
@@ -607,6 +445,8 @@ int hcl_client_connect (hcl_client_t* client, const char* ipaddr, int reuse_addr
 		}
 	}
 
+/* TODO: async connect? */
+/* TODO: connect timeout */
 	if (connect(sck, (struct sockaddr*)&sckaddr, scklen) <= -1)
 	{
 		hcl_client_seterrbfmt (client, HCL_ESYSERR,
@@ -616,12 +456,12 @@ int hcl_client_connect (hcl_client_t* client, const char* ipaddr, int reuse_addr
 
 
 	memset (&proto, 0, HCL_SIZEOF(proto_cb));
-	proto_cb.on_packet = handle_packet;
+	proto_cb.on_packet = client->prim.on_packet;
 
 	proto = hcl_xproto_open(hcl_client_getmmgr(client), &proto_cb, HCL_SIZEOF(*proto_xtn));
 	if (HCL_UNLIKELY(!proto))
 	{
-		fprintf (stderr, "cannot open protocol to %s\n", ipaddr);
+		hcl_client_seterrbfmt (client, HCL_ESYSERR, "cannot open protocol to %s", ipaddr);
 		goto oops;
 	}
 	proto_xtn = hcl_xproto_getxtn(proto);
@@ -636,3 +476,163 @@ oops:
 	if (sck >= 0) close (sck);
 	return -1;
 }
+
+
+static void client_close (hcl_client_t* client)
+{
+	if (client->proto)
+	{
+		hcl_xproto_close (client->proto);
+		client->proto = HCL_NULL;
+	}
+
+	if (client->sck >= 0)
+	{
+		close (client->sck);
+		client->sck = -1;
+	}
+}
+
+int hcl_client_start (hcl_client_t* client, const char* ipaddr, const char* script, int reuse_addr, int shut_wr_after_req)
+{
+	int x;
+	ssize_t n;
+	const char* scptr, * sccur;
+
+	if (client_connect(client, ipaddr, reuse_addr) <= -1) return -1;
+
+	scptr = sccur = script;
+	while (1)
+	{
+		struct pollfd pfd;
+
+		pfd.fd = client->sck;
+		pfd.events = POLLIN;
+		if (*sccur != '\0') pfd.events |= POLLOUT;
+		pfd.revents = 0;
+
+		n = poll(&pfd, 1, 1000);
+		if (n <= -1)
+		{
+			hcl_client_seterrbfmt (client, HCL_ESYSERR, "poll error on %d - %hs", client->sck, strerror(n));
+			goto oops;
+		}
+
+		if (n == 0)
+		{
+			/* TODO: proper timeout handling */
+			continue;
+		}
+
+		if (pfd.revents & POLLERR)
+		{
+			hcl_client_seterrbfmt (client, HCL_ESYSERR, "error condition detected on %d", client->sck);
+			goto oops;
+		}
+
+		if (pfd.revents & POLLOUT)
+		{
+			hcl_xpkt_hdr_t hdr;
+			struct iovec iov[2];
+			hcl_uint16_t seglen;
+
+			while (*sccur != '\0' && sccur - scptr < HCL_XPKT_MAX_PLD_LEN) sccur++;
+
+			seglen = sccur - scptr;
+
+			hdr.id = 1; /* TODO: */
+			hdr.type = HCL_XPKT_CODE | (((seglen >> 8) & 0x0F) << 4);
+			hdr.len = seglen & 0xFF;
+
+			iov[0].iov_base = &hdr;
+			iov[0].iov_len = HCL_SIZEOF(hdr);
+			iov[1].iov_base = scptr;
+			iov[1].iov_len = seglen;
+
+			hcl_sys_send_iov (client->sck, iov, 2); /* TODO: error check */
+
+			scptr = sccur;
+
+			if (*sccur == '\0')
+			{
+				hdr.id = 1; /* TODO: */
+				hdr.type = HCL_XPKT_EXECUTE;
+				hdr.len = 0;
+
+				iov[0].iov_base = &hdr;
+				iov[0].iov_len = HCL_SIZEOF(hdr);
+				hcl_sys_send_iov (client->sck, iov, 1);
+
+				if (shut_wr_after_req)
+				{
+					shutdown (client->sck, SHUT_WR);
+				}
+				else
+				{
+					hdr.type = HCL_XPKT_DISCONNECT;
+					hdr.id = 1; /* TODO: */
+					hdr.len = 0;
+
+					iov[0].iov_base = &hdr;
+					iov[0].iov_len = HCL_SIZEOF(hdr);
+					hcl_sys_send_iov (client->sck, iov, 1);
+				}
+			}
+		}
+
+		if (pfd.revents & POLLIN)
+		{
+			hcl_oow_t bcap;
+			hcl_uint8_t* bptr;
+
+			bptr = hcl_xproto_getbuf(client->proto, &bcap);;
+			x = recv(client->sck, bptr, bcap, 0);
+			if (x <= -1)
+			{
+				if (errno == EINTR) goto carry_on; /* didn't read read */
+				/*hcl_seterrwithsyserr (hcl, 0, errno); */
+				/* TODO: error info set... */
+				return -1;
+			}
+			if (x == 0) hcl_xproto_seteof(client->proto, 1);
+			hcl_xproto_advbuf (client->proto, x);
+		}
+
+
+	carry_on:
+		while (hcl_xproto_ready(client->proto))
+		{
+			if ((n = hcl_xproto_process(client->proto)) <= -1)
+			{
+				/* TODO: proper error message */
+				return -1;
+			}
+			if (n == 0)
+			{
+				/* TODO: chceck if there is remaining data in the buffer...?? */
+				printf ("NO MORE DATA. EXITING...\n");
+				goto done;
+			}
+		}
+
+		if (hcl_xproto_geteof(client->proto)) break;
+	}
+done:
+
+/* TODO: we can check if the buffer has all been consumed. if not, there is trailing garbage.. */
+	/*{
+		struct linger linger;
+		linger.l_onoff = 1;
+		linger.l_linger = 0;
+		setsockopt (client->sck, SOL_SOCKET, SO_LINGER, (char *) &linger, sizeof(linger));
+	}*/
+
+
+	client_close (client);
+	return 0;
+
+oops:
+	client_close (client);
+	return -1;
+}
+
diff --git a/lib/x-server.c b/lib/x-server.c
index 62e3c77..379c39a 100644
--- a/lib/x-server.c
+++ b/lib/x-server.c
@@ -244,12 +244,12 @@ struct hcl_server_t
 };
 
 /* ========================================================================= */
-static int send_stdout_bytes (hcl_xproto_t* proto, const hcl_bch_t* data, hcl_oow_t len);
+static int send_stdout_bytes (hcl_xproto_t* proto, int xpkt_code, const hcl_bch_t* data, hcl_oow_t len);
 
 #if defined(HCL_OOCH_IS_UCH)
-static int send_stdout_chars (hcl_xproto_t* proto, const hcl_ooch_t* data, hcl_oow_t len);
+static int send_stdout_chars (hcl_xproto_t* proto, int xpkt_code, const hcl_ooch_t* data, hcl_oow_t len);
 #else
-#define send_stdout_chars(proto,data,len) send_stdout_bytes(proto,data,len)
+#define send_stdout_chars(proto,xpkt_code,data,len) send_stdout_bytes(proto,xpkt_code,data,len)
 #endif
 
 /* ========================================================================= */
@@ -558,7 +558,7 @@ printf ("IO CLOSE SOMETHING...........\n");
 			hcl_io_udoarg_t* outarg = (hcl_io_udoarg_t*)arg;
 
 printf ("IO WRITE SOMETHING...........\n");
-			if (send_stdout_chars(xtn->worker->proto, outarg->ptr, outarg->len) <= -1)
+			if (send_stdout_chars(xtn->worker->proto, HCL_XPKT_STDOUT, outarg->ptr, outarg->len) <= -1)
 			{
 				/* TODO: change error code and message. propagage the errormessage from proto */
 				hcl_seterrbfmt (hcl, HCL_EIOERR, "failed to write message via proto");
@@ -578,7 +578,7 @@ printf ("IO WRITE SOMETHING...........\n");
 			hcl_io_udoarg_t* outarg = (hcl_io_udoarg_t*)arg;
 
 printf ("IO WRITE SOMETHING BYTES...........\n");
-			if (send_stdout_bytes(xtn->worker->proto, outarg->ptr, outarg->len) <= -1)
+			if (send_stdout_bytes(xtn->worker->proto, HCL_XPKT_STDOUT, outarg->ptr, outarg->len) <= -1)
 			{
 				/* TODO: change error code and message. propagage the errormessage from proto */
 				hcl_seterrbfmt (hcl, HCL_EIOERR, "failed to write message via proto");
@@ -671,26 +671,26 @@ static hcl_server_worker_t* proto_to_worker (hcl_xproto_t* proto)
 
 static int on_fed_cnode (hcl_t* hcl, hcl_cnode_t* obj)
 {
-	/*worker_hcl_xtn_t* xtn = (worker_hcl_xtn_t*)hcl_getxtn(hcl);*/
-	/*hcl_xproto_t* proto = xtn->proto;*/
+	worker_hcl_xtn_t* hcl_xtn = (worker_hcl_xtn_t*)hcl_getxtn(hcl);
+	hcl_server_worker_t* worker;
+	hcl_xproto_t* proto;
 	int flags = 0;
 
-printf ("on_fed_cnode......\n");
+	hcl_xtn = (worker_hcl_xtn_t*)hcl_getxtn(hcl);
+	worker = hcl_xtn->worker;
+	proto = worker->proto;
+
 	/* the compile error must not break the input loop.
 	 * this function returns 0 to go on despite a compile-time error.
 	 *
 	 * if a single line or continued lines contain multiple expressions,
 	 * execution is delayed until the last expression is compiled. */
 
-printf ("COMPILING hcl_copingll......\n");
 	if (hcl_compile(hcl, obj, flags) <= -1)
 	{
-hcl_logbfmt (hcl, HCL_LOG_STDERR, "COMPILER ERROR - %js\n", hcl_geterrmsg(hcl));
-#if 0
-		print_error(hcl, "failed to compile");
-		xtn->feed.pos = xtn->feed.len; /* arrange to discard the rest of the line */
-		show_prompt (hcl, 0);
-#endif
+		const hcl_bch_t* errmsg = hcl_geterrbmsg(hcl);
+		send_stdout_bytes(proto, HCL_XPKT_ERROR, errmsg, hcl_count_bcstr(errmsg));
+/* TODO: ignore the whole line??? */
 	}
 
 	return 0;
@@ -928,7 +928,7 @@ static int kill_server_worker (hcl_xproto_t* proto, hcl_oow_t wid)
 	return xret;
 }
 
-static int handle_packet (hcl_xproto_t* proto, hcl_xpkt_type_t type, const void* data, hcl_oow_t len)
+static int server_on_packet (hcl_xproto_t* proto, hcl_xpkt_type_t type, const void* data, hcl_oow_t len)
 {
 	hcl_server_worker_t* worker;
 	hcl_t* hcl;
@@ -994,7 +994,7 @@ oops:
 	return -1;
 }
 
-static int send_stdout_bytes (hcl_xproto_t* proto, const hcl_bch_t* data, hcl_oow_t len)
+static int send_stdout_bytes (hcl_xproto_t* proto, int xpkt_code, const hcl_bch_t* data, hcl_oow_t len)
 {
 	hcl_server_worker_t* worker;
 	hcl_xpkt_hdr_t hdr;
@@ -1003,6 +1003,7 @@ static int send_stdout_bytes (hcl_xproto_t* proto, const hcl_bch_t* data, hcl_oo
 	hcl_uint16_t seglen;
 
 	worker = proto_to_worker(proto);
+	HCL_ASSERT (worker->hcl, xpkt_code == HCL_XPKT_STDOUT || xpkt_code == HCL_XPKT_STDERR || xpkt_code == HCL_XPKT_ERROR);
 
 	ptr = cur = data;
 	end = data + len;
@@ -1015,7 +1016,7 @@ printf ("SENDING BYTES [%.*s]\n", (int)len, data);
 		seglen = cur - ptr;
 
 		hdr.id = 1; /* TODO: */
-		hdr.type = HCL_XPKT_STDOUT | (((seglen >> 8) & 0x0F) << 4);
+		hdr.type = xpkt_code | (((seglen >> 8) & 0x0F) << 4);
 		hdr.len = seglen & 0xFF;
 
 		iov[0].iov_base = &hdr;
@@ -1037,7 +1038,7 @@ printf ("SENDING BYTES [%.*s]\n", (int)len, data);
 }
 
 #if defined(HCL_OOCH_IS_UCH)
-static int send_stdout_chars (hcl_xproto_t* proto, const hcl_ooch_t* data, hcl_oow_t len)
+static int send_stdout_chars (hcl_xproto_t* proto, int xpkt_code, const hcl_ooch_t* data, hcl_oow_t len)
 {
 	hcl_server_worker_t* worker;
 	const hcl_ooch_t* ptr, * end;
@@ -1057,7 +1058,7 @@ static int send_stdout_chars (hcl_xproto_t* proto, const hcl_ooch_t* data, hcl_o
 		n = hcl_convutobchars(worker->hcl, ptr, &pln, tmp, &tln);
 		if (n <= -1 && n != -2) return -1;
 
-		if (send_stdout_bytes(proto, tmp, tln) <= -1) return -1;
+		if (send_stdout_bytes(proto, xpkt_code, tmp, tln) <= -1) return -1;
 		ptr += pln;
 	}
 
@@ -1560,7 +1561,7 @@ static int init_worker_proto (hcl_server_worker_t* worker)
 	hcl_xproto_cb_t cb;
 
 	HCL_MEMSET (&cb, 0, HCL_SIZEOF(cb));
-	cb.on_packet = handle_packet;
+	cb.on_packet = server_on_packet;
 
 	proto = hcl_xproto_open(hcl_server_getmmgr(worker->server), &cb, HCL_SIZEOF(*xtn));
 	if (HCL_UNLIKELY(!proto)) return -1;