diff --git a/moo/lib/exec.c b/moo/lib/exec.c
index d01f5bc..edaa541 100644
--- a/moo/lib/exec.c
+++ b/moo/lib/exec.c
@@ -1341,34 +1341,6 @@ static int delete_from_sem_io (moo_t* moo, moo_oop_semaphore_t sem, int force)
 	return 0;
 }
 
-void moo_purgesemiosbyhandle (moo_t* moo, moo_ooi_t io_handle)
-{
-	moo_ooi_t index;
-	moo_oop_semaphore_t sem;
-
-	if (io_handle < moo->sem_io_map_capa)
-	{
-		index = moo->sem_io_map[io_handle];
-		if (index >= 0)
-		{
-			MOO_ASSERT(moo, moo->sem_io_tuple[index].handle == io_handle);
-			sem = moo->sem_io_tuple[index].sem[MOO_SEMAPHORE_IO_TYPE_INPUT];
-			if (sem) delete_from_sem_io (moo, sem, 0);
-		}
-	}
-
-	if (io_handle < moo->sem_io_map_capa)
-	{
-		index = moo->sem_io_map[io_handle];
-		if (index >= 0)
-		{
-			MOO_ASSERT(moo, moo->sem_io_tuple[index].handle == io_handle);
-			sem = moo->sem_io_tuple[index].sem[MOO_SEMAPHORE_IO_TYPE_OUTPUT];
-			if (sem) delete_from_sem_io (moo, sem, 0);
-		}
-	}
-}
-
 static void _signal_io_semaphore (moo_t* moo, moo_oop_semaphore_t sem)
 {
 	moo_oop_process_t proc;
@@ -1420,6 +1392,41 @@ static void signal_io_semaphore (moo_t* moo, moo_ooi_t io_handle, moo_ooi_t mask
 		MOO_LOG1 (moo, MOO_LOG_WARN, "Warning - semaphore signaling requested on an unmapped handle %zd\n", io_handle);
 	}
 }
+
+void moo_releaseiohandle (moo_t* moo, moo_ooi_t io_handle)
+{
+	/* TODO: optimize io semapore unmapping. since i'm to close the handle,
+	 *       i don't need to call delete_from_sem_io() seperately for input
+	 *        and output. */
+	if (io_handle < moo->sem_io_map_capa)
+	{
+		moo_ooi_t index;
+		moo_oop_semaphore_t sem;
+
+		index = moo->sem_io_map[io_handle];
+		if (index >= 0)
+		{
+			MOO_ASSERT(moo, moo->sem_io_tuple[index].handle == io_handle);
+			sem = moo->sem_io_tuple[index].sem[MOO_SEMAPHORE_IO_TYPE_INPUT];
+			if (sem) delete_from_sem_io (moo, sem, 0);
+		}
+	}
+
+	if (io_handle < moo->sem_io_map_capa)
+	{
+		moo_ooi_t index;
+		moo_oop_semaphore_t sem;
+
+		index = moo->sem_io_map[io_handle];
+		if (index >= 0)
+		{
+			MOO_ASSERT(moo, moo->sem_io_tuple[index].handle == io_handle);
+			sem = moo->sem_io_tuple[index].sem[MOO_SEMAPHORE_IO_TYPE_OUTPUT];
+			if (sem) delete_from_sem_io (moo, sem, 0);
+		}
+	}
+}
+
 /* ------------------------------------------------------------------------- */
 
 static moo_oop_process_t start_initial_process (moo_t* moo, moo_oop_context_t c)
diff --git a/moo/lib/main.c b/moo/lib/main.c
index 23e377c..894e725 100644
--- a/moo/lib/main.c
+++ b/moo/lib/main.c
@@ -553,7 +553,10 @@ static void* dl_open (moo_t* moo, const moo_ooch_t* name, int flags)
 					goto retry;
 				}
 			}
-			else MOO_DEBUG3 (moo, "Opened(ext) DL %hs[%js] handle %p\n", &bufptr[len], name, handle);
+			else 
+			{
+				MOO_DEBUG3 (moo, "Opened(ext) DL %hs[%js] handle %p\n", &bufptr[len], name, handle);
+			}
 		}
 		else
 		{
@@ -749,12 +752,13 @@ static void log_write (moo_t* moo, moo_oow_t mask, const moo_ooch_t* msg, moo_oo
 	}
 	else
 	{
-		if (!(xtn->logmask & mask & ~MOO_LOG_ALL_LEVELS)) return; /* check log types */
-		if (!(xtn->logmask & mask & ~MOO_LOG_ALL_TYPES)) return; /* check log levels */
+		if (!(xtn->logmask & mask & ~MOO_LOG_ALL_LEVELS)) return;  /* check log types */
+		if (!(xtn->logmask & mask & ~MOO_LOG_ALL_TYPES)) return;  /* check log levels */
 
 		if (mask & MOO_LOG_STDOUT) logfd = 1;
 		else
 		{
+
 			logfd = xtn->logfd;
 			if (logfd <= -1) return;
 		}
@@ -2045,7 +2049,7 @@ static void clear_sigterm (void)
 }
 /* ========================================================================= */
 
-static void close_moo (moo_t* moo)
+static void fini_moo (moo_t* moo)
 {
 	xtn_t* xtn = moo_getxtn(moo);
 	if (xtn->logfd >= 0)
@@ -2054,7 +2058,6 @@ static void close_moo (moo_t* moo)
 		xtn->logfd = -1;
 		xtn->logfd_istty = 0;
 	}
-	moo_close (moo);
 }
 
 static int handle_logopt (moo_t* moo, const moo_bch_t* str)
@@ -2171,6 +2174,7 @@ int main (int argc, char* argv[])
 	moo_oocs_t objname;
 	moo_oocs_t mthname;
 	moo_vmprim_t vmprim;
+	moo_cb_t moocb;
 	int i, xret;
 
 	moo_bci_t c;
@@ -2300,11 +2304,15 @@ int main (int argc, char* argv[])
 	xtn->logfd = -1;
 	xtn->logfd_istty = 0;
 
+	memset (&moocb, 0, MOO_SIZEOF(moocb));
+	moocb.fini = fini_moo;
+	moo_regcb (moo, &moocb);
+
 	if (logopt)
 	{
 		if (handle_logopt (moo, logopt) <= -1) 
 		{
-			close_moo (moo);
+			moo_close (moo);
 			return -1;
 		}
 	}
@@ -2319,7 +2327,7 @@ int main (int argc, char* argv[])
 	{
 		if (handle_dbgopt (moo, dbgopt) <= -1)
 		{
-			close_moo (moo);
+			moo_close (moo);
 			return -1;
 		}
 	}
@@ -2328,7 +2336,7 @@ int main (int argc, char* argv[])
 	if (moo_ignite(moo) <= -1)
 	{
 		moo_logbfmt (moo, MOO_LOG_STDERR, "ERROR: cannot ignite moo - [%d] %js\n", moo_geterrnum(moo), moo_geterrstr(moo));
-		close_moo (moo);
+		moo_close (moo);
 		return -1;
 	}
 
@@ -2380,7 +2388,7 @@ int main (int argc, char* argv[])
 				moo_logbfmt (moo, MOO_LOG_STDERR, "ERROR: cannot compile code - [%d] %js\n", moo_geterrnum(moo), moo_geterrmsg(moo));
 			}
 
-			close_moo (moo);
+			moo_close (moo);
 #if defined(USE_LTDL)
 			lt_dlexit ();
 #endif
@@ -2411,7 +2419,7 @@ int main (int argc, char* argv[])
 	/*moo_dumpsymtab(moo);
 	 *moo_dumpdic(moo, moo->sysdic, "System dictionary");*/
 
-	close_moo (moo);
+	moo_close (moo);
 
 #if defined(USE_LTDL)
 	lt_dlexit ();
diff --git a/moo/lib/moo.c b/moo/lib/moo.c
index 8de89b4..f07d49d 100644
--- a/moo/lib/moo.c
+++ b/moo/lib/moo.c
@@ -203,14 +203,14 @@ void moo_fini (moo_t* moo)
 		moo->proc_map_free_last = -1;
 	}
 
+	moo_rbt_walk (&moo->modtab, unload_module, moo); /* unload all modules */
+	moo_rbt_fini (&moo->modtab);
+
 	for (cb = moo->cblist; cb; cb = cb->next)
 	{
 		if (cb->fini) cb->fini (moo);
 	}
 
-	moo_rbt_walk (&moo->modtab, unload_module, moo); /* unload all modules */
-	moo_rbt_fini (&moo->modtab);
-
 /* TOOD: persistency? storing objects to image file? */
 
 	moo_killheap (moo, moo->newheap);
diff --git a/moo/lib/moo.h b/moo/lib/moo.h
index 10e4caa..1469fa0 100644
--- a/moo/lib/moo.h
+++ b/moo/lib/moo.h
@@ -2153,11 +2153,11 @@ MOO_EXPORT const moo_ooch_t* moo_errnum_to_errstr (
 );
 
 /**
- * The moo_purgesemiosbyhandle() function deletes IO semaphores associated
- * with the given IO handle. It can be called usefaully when you close 
- * a IO handle with dangling semaphores associated.
+ * The moo_releaseiohandle() function deletes resources associated with
+ * the given IO handle. The resources include IO semaphores. You should call
+ * this function before closing an IO handle.
  */
-MOO_EXPORT void moo_purgesemiosbyhandle (
+MOO_EXPORT void moo_releaseiohandle (
 	moo_t*    moo,
 	moo_ooi_t io_handle
 );
diff --git a/moo/mod/sck.c b/moo/mod/sck.c
index e36c7e6..3bbb144 100644
--- a/moo/mod/sck.c
+++ b/moo/mod/sck.c
@@ -132,7 +132,7 @@ static moo_pfrc_t pf_close_socket (moo_t* moo, moo_ooi_t nargs)
 	fd = MOO_OOP_TO_SMOOI(sck->handle);
 	if (fd >= 0)
 	{
-		moo_purgesemiobyhandle (moo, MOO_OOP_TO_SMOOI(sck->handle));
+		moo_releaseiohandle (moo, MOO_OOP_TO_SMOOI(sck->handle));
 		if (close(MOO_OOP_TO_SMOOI(sck->handle)) == -1)
 		{
 			moo_seterrwithsyserr (moo, errno);