diff --git a/mio/lib/dns.c b/mio/lib/dns.c
index d85d639..ff4a742 100644
--- a/mio/lib/dns.c
+++ b/mio/lib/dns.c
@@ -99,12 +99,13 @@ static mio_oow_t dn_length (mio_uint8_t* ptr, mio_oow_t len)
 
 struct mio_dnss_t
 {
-	mio_t* mio;
+	MIO_SVC_HEADERS;
 };
 
 struct mio_dnsc_t
 {
-	mio_t* mio;
+	MIO_SVC_HEADERS;
+
 	mio_dev_sck_t* sck;
 	mio_sckaddr_t serveraddr;
 	mio_oow_t seq;
@@ -158,7 +159,6 @@ static void dns_on_disconnect (mio_dev_sck_t* dev)
 {
 }
 
-
 mio_dnsc_t* mio_dnsc_start (mio_t* mio)
 {
 	mio_dnsc_t* dnsc = MIO_NULL;
@@ -168,6 +168,7 @@ mio_dnsc_t* mio_dnsc_start (mio_t* mio)
 	if (!dnsc) goto oops;
 
 	dnsc->mio = mio;
+	dnsc->stop = mio_dnsc_stop;
 
 	MIO_MEMSET (&minfo, 0, MIO_SIZEOF(minfo));
 	minfo.type = MIO_DEV_SCK_UDP4; /* or UDP6 depending on the binding address */
@@ -185,12 +186,14 @@ mio_uint32_t ia = 0x01010101; /* 1.1.1.1 */
 	mio_sckaddr_initforip4 (&dnsc->serveraddr, 53, (mio_ip4addr_t*)&ia);
 }
 
+	MIO_SVC_REGISTER (mio, (mio_svc_t*)dnsc);
 	return dnsc;
 
 oops:
 	if (dnsc)
 	{
 		if (dnsc->sck) mio_dev_sck_kill (dnsc->sck);
+		mio_freemem (mio, dnsc);
 	}
 	return MIO_NULL;
 }
@@ -198,6 +201,8 @@ oops:
 void mio_dnsc_stop (mio_dnsc_t* dnsc)
 {
 	mio_t* mio = dnsc->mio;
+	if (dnsc->sck) mio_dev_sck_kill (dnsc->sck);
+	MIO_SVC_UNREGISTER (mio, dnsc);
 	mio_freemem (mio, dnsc);
 }
 
diff --git a/mio/lib/main.c b/mio/lib/main.c
index ddcd368..9c9979f 100644
--- a/mio/lib/main.c
+++ b/mio/lib/main.c
@@ -658,7 +658,7 @@ int main (int argc, char* argv[])
 	sin.sin_family = AF_INET;
 	sin.sin_port = htons(1234); */
 /*
-	udp = (mio_dev_udp_t*)mio_makedev(mio, MIO_SIZEOF(*udp), &udp_mth, &udp_evcb, &sin);
+	udp = (mio_dev_udp_t*)mio_dev_make(mio, MIO_SIZEOF(*udp), &udp_mth, &udp_evcb, &sin);
 	if (!udp)
 	{
 		printf ("Cannot make udp\n");
diff --git a/mio/lib/mio-pro.c b/mio/lib/mio-pro.c
index ad1b452..ff2190f 100644
--- a/mio/lib/mio-pro.c
+++ b/mio/lib/mio-pro.c
@@ -758,17 +758,17 @@ static mio_dev_pro_slave_t* make_slave (mio_t* mio, slave_info_t* si)
 	switch (si->id)
 	{
 		case MIO_DEV_PRO_IN:
-			return (mio_dev_pro_slave_t*)mio_makedev(
+			return (mio_dev_pro_slave_t*)mio_dev_make(
 				mio, MIO_SIZEOF(mio_dev_pro_t), 
 				&dev_pro_methods_slave, &dev_pro_event_callbacks_slave_in, si);
 
 		case MIO_DEV_PRO_OUT:
-			return (mio_dev_pro_slave_t*)mio_makedev(
+			return (mio_dev_pro_slave_t*)mio_dev_make(
 				mio, MIO_SIZEOF(mio_dev_pro_t), 
 				&dev_pro_methods_slave, &dev_pro_event_callbacks_slave_out, si);
 
 		case MIO_DEV_PRO_ERR:
-			return (mio_dev_pro_slave_t*)mio_makedev(
+			return (mio_dev_pro_slave_t*)mio_dev_make(
 				mio, MIO_SIZEOF(mio_dev_pro_t), 
 				&dev_pro_methods_slave, &dev_pro_event_callbacks_slave_err, si);
 
@@ -780,7 +780,7 @@ static mio_dev_pro_slave_t* make_slave (mio_t* mio, slave_info_t* si)
 
 mio_dev_pro_t* mio_dev_pro_make (mio_t* mio, mio_oow_t xtnsize, const mio_dev_pro_make_t* info)
 {
-	return (mio_dev_pro_t*)mio_makedev(
+	return (mio_dev_pro_t*)mio_dev_make(
 		mio, MIO_SIZEOF(mio_dev_pro_t) + xtnsize, 
 		&dev_pro_methods, &dev_pro_event_callbacks, (void*)info);
 }
diff --git a/mio/lib/mio-sck.c b/mio/lib/mio-sck.c
index ed81734..e3b0276 100644
--- a/mio/lib/mio-sck.c
+++ b/mio/lib/mio-sck.c
@@ -1350,7 +1350,7 @@ accept_done:
 	 * instead of MIO_SIZEOF(mio_dev_sck_t). therefore, the 
 	 * extension area as big as that of the master sck device
 	 * is created in the client sck device */
-	clidev = (mio_dev_sck_t*)mio_makedev(mio, rdev->dev_size, &dev_mth_clisck, rdev->dev_evcb, &clisck); 
+	clidev = (mio_dev_sck_t*)mio_dev_make(mio, rdev->dev_size, &dev_mth_clisck, rdev->dev_evcb, &clisck); 
 	if (!clidev) 
 	{
 		close (clisck);
@@ -1699,13 +1699,13 @@ mio_dev_sck_t* mio_dev_sck_make (mio_t* mio, mio_oow_t xtnsize, const mio_dev_sc
 
 	if (sck_type_map[info->type].extra_dev_cap & MIO_DEV_CAP_STREAM) /* can't use the IS_STATEFUL() macro yet */
 	{
-		rdev = (mio_dev_sck_t*)mio_makedev(
+		rdev = (mio_dev_sck_t*)mio_dev_make(
 			mio, MIO_SIZEOF(mio_dev_sck_t) + xtnsize, 
 			&dev_sck_methods_stateful, &dev_sck_event_callbacks_stateful, (void*)info);
 	}
 	else
 	{
-		rdev = (mio_dev_sck_t*)mio_makedev(
+		rdev = (mio_dev_sck_t*)mio_dev_make(
 			mio, MIO_SIZEOF(mio_dev_sck_t) + xtnsize,
 			&dev_sck_methods_stateless, &dev_sck_event_callbacks_stateless, (void*)info);
 	}
diff --git a/mio/lib/mio.c b/mio/lib/mio.c
index d690442..d2712e3 100644
--- a/mio/lib/mio.c
+++ b/mio/lib/mio.c
@@ -47,6 +47,9 @@ static int kill_and_free_device (mio_dev_t* dev, int force);
 } while (0)
 
 
+
+
+
 static void on_read_timeout (mio_t* mio, const mio_ntime_t* now, mio_tmrjob_t* job);
 static void on_write_timeout (mio_t* mio, const mio_ntime_t* now, mio_tmrjob_t* job);
 
@@ -149,6 +152,20 @@ void mio_fini (mio_t* mio)
 		}
 	}
 
+	while (mio->actsvc.head)
+	{
+		if (mio->actsvc.head->stop) 
+		{
+			/* the stop callback must unregister itself */
+			mio->actsvc.head->stop (mio->actsvc.head);
+		}
+		else
+		{
+			/* unregistration only if no stop callback is designated */
+			MIO_SVC_UNREGISTER (mio, mio->actsvc.head);
+		}
+	}
+
 	/* kill all registered devices */
 	while (mio->actdev.head)
 	{
@@ -613,7 +630,7 @@ int mio_loop (mio_t* mio)
 	return 0;
 }
 
-mio_dev_t* mio_makedev (mio_t* mio, mio_oow_t dev_size, mio_dev_mth_t* dev_mth, mio_dev_evcb_t* dev_evcb, void* make_ctx)
+mio_dev_t* mio_dev_make (mio_t* mio, mio_oow_t dev_size, mio_dev_mth_t* dev_mth, mio_dev_evcb_t* dev_evcb, void* make_ctx)
 {
 	mio_dev_t* dev;
 
diff --git a/mio/lib/mio.h b/mio/lib/mio.h
index 2e0328d..e99372e 100644
--- a/mio/lib/mio.h
+++ b/mio/lib/mio.h
@@ -55,6 +55,7 @@ typedef struct mio_t mio_t;
 typedef struct mio_dev_t mio_dev_t;
 typedef struct mio_dev_mth_t mio_dev_mth_t;
 typedef struct mio_dev_evcb_t mio_dev_evcb_t;
+typedef struct mio_svc_t mio_svc_t;
 
 typedef struct mio_q_t mio_q_t;
 typedef struct mio_wq_t mio_wq_t;
@@ -156,11 +157,11 @@ struct mio_tmrjob_t
 struct mio_dev_mth_t
 {
 	/* ------------------------------------------------------------------ */
-	/* mandatory. called in mio_makedev() */
+	/* mandatory. called in mio_dev_make() */
 	int           (*make)         (mio_dev_t* dev, void* ctx); 
 
 	/* ------------------------------------------------------------------ */
-	/* mandatory. called in mio_dev_kill(). also called in mio_makedev() upon
+	/* mandatory. called in mio_dev_kill(). also called in mio_dev_make() upon
 	 * failure after make() success.
 	 * 
 	 * when 'force' is 0, the return value of -1 causes the device to be a
@@ -175,7 +176,7 @@ struct mio_dev_mth_t
 	int           (*kill)         (mio_dev_t* dev, int force); 
 
 	/* ------------------------------------------------------------------ */
-	mio_syshnd_t (*getsyshnd)    (mio_dev_t* dev); /* mandatory. called in mio_makedev() after successful make() */
+	mio_syshnd_t (*getsyshnd)    (mio_dev_t* dev); /* mandatory. called in mio_dev_make() after successful make() */
 
 
 	/* ------------------------------------------------------------------ */
@@ -382,6 +383,45 @@ typedef enum mio_dev_event_t mio_dev_event_t;
 #define MIO_CWQFL_SIZE 16
 #define MIO_CWQFL_ALIGN 16
 
+
+/* =========================================================================
+ * SERVICE 
+ * ========================================================================= */
+
+typedef void (*mio_svc_stop_t) (mio_svc_t* svc);
+
+#define MIO_SVC_HEADERS \
+	mio_t*          mio; \
+	mio_svc_stop_t  stop; \
+	mio_svc_t*      svc_prev; \
+	mio_svc_t*      svc_next 
+
+/* the stop callback is called if it's not NULL and the service is still 
+ * alive when mio_close() is reached. it still calls MIO_SVC_UNREGISTER()
+ * if the stop callback is NULL. The stop callback, if specified, must
+ * call MIO_SVC_UNREGISTER(). */ 
+
+struct mio_svc_t
+{
+	MIO_SVC_HEADERS;
+};
+
+#define MIO_SVC_REGISTER(mio,svc) do { \
+	if ((mio)->actsvc.tail) (mio)->actsvc.tail->svc_next = (svc); \
+	else (mio)->actsvc.head = (svc); \
+	(svc)->svc_prev = (mio)->actsvc.tail; \
+	(svc)->svc_next = MIO_NULL; \
+	(mio)->actsvc.tail = (svc); \
+} while(0)
+
+#define MIO_SVC_UNREGISTER(mio,svc) do { \
+	if ((svc)->svc_prev) (svc)->svc_prev->svc_next = (svc)->svc_next; \
+	else (mio)->actsvc.head = (svc)->svc_next; \
+	if ((svc)->svc_next) (svc)->svc_next->svc_prev = (svc)->svc_prev; \
+	else (mio)->actsvc.tail = (svc)->svc_prev; \
+} while (0)
+
+
 /* =========================================================================
  * MIO LOGGING
  * ========================================================================= */
@@ -545,6 +585,12 @@ struct mio_t
 	mio_cwq_t cwq;
 	mio_cwq_t* cwqfl[MIO_CWQFL_SIZE]; /* list of free cwq objects */
 
+	struct
+	{
+		mio_svc_t* head;
+		mio_svc_t* tail;
+	} actsvc; /* active services */
+
 	/* platform specific fields below */
 	mio_sys_t* sysdep;
 };
@@ -680,7 +726,9 @@ MIO_EXPORT void mio_stop (
 	mio_stopreq_t stopreq
 );
 
-MIO_EXPORT mio_dev_t* mio_makedev (
+
+
+MIO_EXPORT mio_dev_t* mio_dev_make (
 	mio_t*           mio,
 	mio_oow_t        dev_size,
 	mio_dev_mth_t*   dev_mth,