diff --git a/mio/Makefile.in b/mio/Makefile.in
index 2fe5d77..e8308fe 100644
--- a/mio/Makefile.in
+++ b/mio/Makefile.in
@@ -347,7 +347,6 @@ pdfdir = @pdfdir@
 prefix = @prefix@
 program_transform_name = @program_transform_name@
 psdir = @psdir@
-runstatedir = @runstatedir@
 sbindir = @sbindir@
 sharedstatedir = @sharedstatedir@
 srcdir = @srcdir@
@@ -578,7 +577,7 @@ distdir: $(DISTFILES)
 	  ! -type d ! -perm -444 -exec $(install_sh) -c -m a+r {} {} \; \
 	|| chmod -R a+r "$(distdir)"
 dist-gzip: distdir
-	tardir=$(distdir) && $(am__tar) | GZIP=$(GZIP_ENV) gzip -c >$(distdir).tar.gz
+	tardir=$(distdir) && $(am__tar) | eval GZIP= gzip $(GZIP_ENV) -c >$(distdir).tar.gz
 	$(am__post_remove_distdir)
 
 dist-bzip2: distdir
@@ -604,7 +603,7 @@ dist-shar: distdir
 	@echo WARNING: "Support for shar distribution archives is" \
 	               "deprecated." >&2
 	@echo WARNING: "It will be removed altogether in Automake 2.0" >&2
-	shar $(distdir) | GZIP=$(GZIP_ENV) gzip -c >$(distdir).shar.gz
+	shar $(distdir) | eval GZIP= gzip $(GZIP_ENV) -c >$(distdir).shar.gz
 	$(am__post_remove_distdir)
 
 dist-zip: distdir
@@ -622,7 +621,7 @@ dist dist-all:
 distcheck: dist
 	case '$(DIST_ARCHIVES)' in \
 	*.tar.gz*) \
-	  GZIP=$(GZIP_ENV) gzip -dc $(distdir).tar.gz | $(am__untar) ;;\
+	  eval GZIP= gzip $(GZIP_ENV) -dc $(distdir).tar.gz | $(am__untar) ;;\
 	*.tar.bz2*) \
 	  bzip2 -dc $(distdir).tar.bz2 | $(am__untar) ;;\
 	*.tar.lz*) \
@@ -632,7 +631,7 @@ distcheck: dist
 	*.tar.Z*) \
 	  uncompress -c $(distdir).tar.Z | $(am__untar) ;;\
 	*.shar.gz*) \
-	  GZIP=$(GZIP_ENV) gzip -dc $(distdir).shar.gz | unshar ;;\
+	  eval GZIP= gzip $(GZIP_ENV) -dc $(distdir).shar.gz | unshar ;;\
 	*.zip*) \
 	  unzip $(distdir).zip ;;\
 	esac
diff --git a/mio/configure b/mio/configure
index e18106a..6fce15c 100755
--- a/mio/configure
+++ b/mio/configure
@@ -771,7 +771,6 @@ infodir
 docdir
 oldincludedir
 includedir
-runstatedir
 localstatedir
 sharedstatedir
 sysconfdir
@@ -862,7 +861,6 @@ datadir='${datarootdir}'
 sysconfdir='${prefix}/etc'
 sharedstatedir='${prefix}/com'
 localstatedir='${prefix}/var'
-runstatedir='${localstatedir}/run'
 includedir='${prefix}/include'
 oldincludedir='/usr/include'
 docdir='${datarootdir}/doc/${PACKAGE_TARNAME}'
@@ -1115,15 +1113,6 @@ do
   | -silent | --silent | --silen | --sile | --sil)
     silent=yes ;;
 
-  -runstatedir | --runstatedir | --runstatedi | --runstated \
-  | --runstate | --runstat | --runsta | --runst | --runs \
-  | --run | --ru | --r)
-    ac_prev=runstatedir ;;
-  -runstatedir=* | --runstatedir=* | --runstatedi=* | --runstated=* \
-  | --runstate=* | --runstat=* | --runsta=* | --runst=* | --runs=* \
-  | --run=* | --ru=* | --r=*)
-    runstatedir=$ac_optarg ;;
-
   -sbindir | --sbindir | --sbindi | --sbind | --sbin | --sbi | --sb)
     ac_prev=sbindir ;;
   -sbindir=* | --sbindir=* | --sbindi=* | --sbind=* | --sbin=* \
@@ -1261,7 +1250,7 @@ fi
 for ac_var in	exec_prefix prefix bindir sbindir libexecdir datarootdir \
 		datadir sysconfdir sharedstatedir localstatedir includedir \
 		oldincludedir docdir infodir htmldir dvidir pdfdir psdir \
-		libdir localedir mandir runstatedir
+		libdir localedir mandir
 do
   eval ac_val=\$$ac_var
   # Remove trailing slashes.
@@ -1414,7 +1403,6 @@ Fine tuning of the installation directories:
   --sysconfdir=DIR        read-only single-machine data [PREFIX/etc]
   --sharedstatedir=DIR    modifiable architecture-independent data [PREFIX/com]
   --localstatedir=DIR     modifiable single-machine data [PREFIX/var]
-  --runstatedir=DIR       modifiable per-process data [LOCALSTATEDIR/run]
   --libdir=DIR            object code libraries [EPREFIX/lib]
   --includedir=DIR        C header files [PREFIX/include]
   --oldincludedir=DIR     C header files for non-gcc [/usr/include]
diff --git a/mio/lib/Makefile.in b/mio/lib/Makefile.in
index 41988ee..68eb2a3 100644
--- a/mio/lib/Makefile.in
+++ b/mio/lib/Makefile.in
@@ -365,7 +365,6 @@ pdfdir = @pdfdir@
 prefix = @prefix@
 program_transform_name = @program_transform_name@
 psdir = @psdir@
-runstatedir = @runstatedir@
 sbindir = @sbindir@
 sharedstatedir = @sharedstatedir@
 srcdir = @srcdir@
diff --git a/mio/lib/fmtout.c b/mio/lib/fmtout.c
index 4775209..3ceb31c 100644
--- a/mio/lib/fmtout.c
+++ b/mio/lib/fmtout.c
@@ -517,16 +517,14 @@ static int put_errcs (mio_t* mio, mio_bitmask_t mask, const mio_ooch_t* ptr, mio
 }
 
 
-static mio_ooi_t __errbfmtv (mio_t* mio, mio_bitmask_t mask, const mio_bch_t* fmt, ...);
-
 static int _errbfmtv (mio_t* mio, const mio_bch_t* fmt, mio_fmtout_data_t* data, va_list ap)
 {
-	return __logbfmtv (mio, fmt, data, ap);
+	return __logbfmtv(mio, fmt, data, ap);
 }
 
 static int _errufmtv (mio_t* mio, const mio_uch_t* fmt, mio_fmtout_data_t* data, va_list ap)
 {
-	return __logufmtv (mio, fmt, data, ap);
+	return __logufmtv(mio, fmt, data, ap);
 }
 
 void mio_seterrbfmt (mio_t* mio, mio_errnum_t errnum, const mio_bch_t* fmt, ...)
@@ -651,8 +649,6 @@ static int put_sprch (mio_t* mio, mio_bitmask_t mask, mio_ooch_t ch, mio_oow_t l
 	return 1; /* success */
 }
 
-static mio_ooi_t __sprbfmtv (mio_t* mio, mio_bitmask_t mask, const mio_bch_t* fmt, ...);
-
 static int _sprbfmtv (mio_t* mio, const mio_bch_t* fmt, mio_fmtout_data_t* data, va_list ap)
 {
 	return __logbfmtv (mio, fmt, data, ap);
diff --git a/mio/lib/main.c b/mio/lib/main.c
index 77c43ae..e5641c4 100644
--- a/mio/lib/main.c
+++ b/mio/lib/main.c
@@ -174,7 +174,10 @@ static void tcp_sck_on_connect (mio_dev_sck_t* tcp)
 
 	if (tcp->state & MIO_DEV_SCK_CONNECTED)
 	{
-printf ("DEVICE connected to a remote server... LOCAL %s:%d REMOTE %s:%d.", buf1, mio_getsckaddrport(&tcp->localaddr), buf2, mio_getsckaddrport(&tcp->remoteaddr));
+		mio_logbfmt (tcp->mio, MIO_LOG_UNTYPED | MIO_LOG_INFO, "DEVICE connected to a remote server... LOCAL %hs:%d REMOTE %hs:%d.", 
+			buf1, mio_getsckaddrport(&tcp->localaddr), buf2, mio_getsckaddrport(&tcp->remoteaddr));
+printf ("DEVICE connected to a remote server... LOCAL %s:%d REMOTE %s:%d.", 
+			buf1, mio_getsckaddrport(&tcp->localaddr), buf2, mio_getsckaddrport(&tcp->remoteaddr));
 	}
 	else if (tcp->state & MIO_DEV_SCK_ACCEPTED)
 	{
diff --git a/mio/lib/mio-pro.c b/mio/lib/mio-pro.c
index 556f549..13adf33 100644
--- a/mio/lib/mio-pro.c
+++ b/mio/lib/mio-pro.c
@@ -714,19 +714,19 @@ static int pro_ready_slave (mio_dev_t* dev, int events)
 static int pro_on_read_slave_out (mio_dev_t* dev, const void* data, mio_iolen_t len, const mio_devaddr_t* srcaddr)
 {
 	mio_dev_pro_slave_t* pro = (mio_dev_pro_slave_t*)dev;
-	return pro->master->on_read (pro->master, data, len, MIO_DEV_PRO_OUT);
+	return pro->master->on_read(pro->master, data, len, MIO_DEV_PRO_OUT);
 }
 
 static int pro_on_read_slave_err (mio_dev_t* dev, const void* data, mio_iolen_t len, const mio_devaddr_t* srcaddr)
 {
 	mio_dev_pro_slave_t* pro = (mio_dev_pro_slave_t*)dev;
-	return pro->master->on_read (pro->master, data, len, MIO_DEV_PRO_ERR);
+	return pro->master->on_read(pro->master, data, len, MIO_DEV_PRO_ERR);
 }
 
 static int pro_on_write_slave (mio_dev_t* dev, mio_iolen_t wrlen, void* wrctx, const mio_devaddr_t* dstaddr)
 {
 	mio_dev_pro_slave_t* pro = (mio_dev_pro_slave_t*)dev;
-	return pro->master->on_write (pro->master, wrlen, wrctx);
+	return pro->master->on_write(pro->master, wrlen, wrctx);
 }
 
 static mio_dev_evcb_t dev_pro_event_callbacks_slave_in =
@@ -772,7 +772,7 @@ static mio_dev_pro_slave_t* make_slave (mio_t* mio, slave_info_t* si)
 				&dev_pro_methods_slave, &dev_pro_event_callbacks_slave_err, si);
 
 		default:
-			mio->errnum = MIO_EINVAL;
+			mio_seterrnum (mio, MIO_EINVAL);
 			return MIO_NULL;
 	}
 }
@@ -797,7 +797,7 @@ int mio_dev_pro_write (mio_dev_pro_t* dev, const void* data, mio_iolen_t dlen, v
 	}
 	else
 	{
-		dev->mio->errnum = MIO_ENOCAPA; /* TODO: is it the right error number? */
+		mio_seterrnum (dev->mio, MIO_ENOCAPA); /* TODO: is it the right error number? */
 		return -1;
 	}
 }
@@ -810,19 +810,19 @@ int mio_dev_pro_timedwrite (mio_dev_pro_t* dev, const void* data, mio_iolen_t dl
 	}
 	else
 	{
-		dev->mio->errnum = MIO_ENOCAPA; /* TODO: is it the right error number? */
+		mio_seterrnum (dev->mio, MIO_ENOCAPA); /* TODO: is it the right error number? */
 		return -1;
 	}
 }
 
 int mio_dev_pro_close (mio_dev_pro_t* dev, mio_dev_pro_sid_t sid)
 {
-	return mio_dev_ioctl ((mio_dev_t*)dev, MIO_DEV_PRO_CLOSE, &sid);
+	return mio_dev_ioctl((mio_dev_t*)dev, MIO_DEV_PRO_CLOSE, &sid);
 }
 
 int mio_dev_pro_killchild (mio_dev_pro_t* dev)
 {
-	return mio_dev_ioctl ((mio_dev_t*)dev, MIO_DEV_PRO_KILL_CHILD, MIO_NULL);
+	return mio_dev_ioctl((mio_dev_t*)dev, MIO_DEV_PRO_KILL_CHILD, MIO_NULL);
 }
 
 #if 0
diff --git a/mio/lib/mio-prv.h b/mio/lib/mio-prv.h
index 66453bc..65254e4 100644
--- a/mio/lib/mio-prv.h
+++ b/mio/lib/mio-prv.h
@@ -47,7 +47,7 @@
 #if defined(MIO_BUILD_RELEASE)
 #	define MIO_ASSERT(mio,expr) ((void)0)
 #else
-#	define MIO_ASSERT(mio,expr) ((void)((expr) || mio_sys_assertfail(mio, #expr, __FILE__, __LINE__), 0)))
+#	define MIO_ASSERT(mio,expr) ((void)((expr) || (mio_sys_assertfail(mio, #expr, __FILE__, __LINE__), 0)))
 #endif
 
 
@@ -152,7 +152,7 @@ mio_errnum_t mio_sys_syserrstrb (
 
 
 
-void mio_sys_initlog (
+int mio_sys_initlog (
 	mio_t*            mio
 );
 
diff --git a/mio/lib/mio-sck.c b/mio/lib/mio-sck.c
index ae056a7..56dbe9d 100644
--- a/mio/lib/mio-sck.c
+++ b/mio/lib/mio-sck.c
@@ -164,7 +164,7 @@ int mio_getsckaddrinfo (mio_t* mio, const mio_sckaddr_t* addr, mio_scklen_t* len
 		/* TODO: more address type */
 	}
 
-	mio->errnum = MIO_EINVAL;
+	mio_seterrnum (mio, MIO_EINVAL);
 	return -1;
 }
 
@@ -272,7 +272,6 @@ static mio_devaddr_t* sckaddr_to_devaddr (mio_dev_sck_t* dev, const mio_sckaddr_
 	if (sckaddr)
 	{
 		mio_scklen_t len;
-
 		mio_getsckaddrinfo (dev->mio, sckaddr, &len, MIO_NULL);
 		devaddr->ptr = (void*)sckaddr;
 		devaddr->len = len;
@@ -411,21 +410,30 @@ static int schedule_timer_job_after (mio_dev_sck_t* dev, const mio_ntime_t* fire
 }
 
 /* ======================================================================== */
+#if defined(USE_SSL)
+static void set_ssl_error (mio_t* mio, int sslerr)
+{
+	mio_bch_t emsg[128];
+	ERR_error_string_n (sslerr, emsg, MIO_COUNTOF(emsg));
+	mio_seterrbfmt (mio, MIO_ESYSERR, "%hs", emsg);
+}
+#endif
 
 static int dev_sck_make (mio_dev_t* dev, void* ctx)
 {
+	mio_t* mio = dev->mio;
 	mio_dev_sck_t* rdev = (mio_dev_sck_t*)dev;
 	mio_dev_sck_make_t* arg = (mio_dev_sck_make_t*)ctx;
 
-	MIO_ASSERT (dev->mio, arg->type >= 0 && arg->type < MIO_COUNTOF(sck_type_map));
+	MIO_ASSERT (mio, arg->type >= 0 && arg->type < MIO_COUNTOF(sck_type_map));
 
 	if (sck_type_map[arg->type].domain <= -1)
 	{
-		dev->mio->errnum = MIO_ENOIMPL;
+		mio_seterrnum (mio, MIO_ENOIMPL); /* TODO: better error info? */
 		return -1;
 	}
 
-	rdev->sck = open_async_socket(dev->mio, sck_type_map[arg->type].domain, sck_type_map[arg->type].type, sck_type_map[arg->type].proto);
+	rdev->sck = open_async_socket(mio, sck_type_map[arg->type].domain, sck_type_map[arg->type].type, sck_type_map[arg->type].proto);
 	if (rdev->sck == MIO_SCKHND_INVALID) goto oops;
 
 	rdev->dev_capa = MIO_DEV_CAPA_IN | MIO_DEV_CAPA_OUT | sck_type_map[arg->type].extra_dev_capa;
@@ -441,7 +449,7 @@ static int dev_sck_make (mio_dev_t* dev, void* ctx)
 oops:
 	if (rdev->sck != MIO_SCKHND_INVALID)
 	{
-		close_async_socket (rdev->mio, rdev->sck);
+		close_async_socket (mio, rdev->sck);
 		rdev->sck = MIO_SCKHND_INVALID;
 	}
 	return -1;
@@ -449,6 +457,7 @@ oops:
 
 static int dev_sck_make_client (mio_dev_t* dev, void* ctx)
 {
+	mio_t* mio = dev->mio;
 	mio_dev_sck_t* rdev = (mio_dev_sck_t*)dev;
 	mio_syshnd_t* sck = (mio_syshnd_t*)ctx;
 
@@ -461,13 +470,13 @@ static int dev_sck_make_client (mio_dev_t* dev, void* ctx)
 	rdev->sck = *sck;
 	rdev->tmrjob_index = MIO_TMRIDX_INVALID;
 
-	if (mio_makesckasync(rdev->mio, rdev->sck) <= -1) return -1;
+	if (mio_makesckasync(mio, rdev->sck) <= -1) return -1;
 #if defined(FD_CLOEXEC)
 	{
 		int flags = fcntl(rdev->sck, F_GETFD, 0);
 		if (fcntl(rdev->sck, F_SETFD, flags | FD_CLOEXEC) == -1)
 		{
-			mio_seterrwithsyserr (rdev->mio, 0, errno);
+			mio_seterrbfmtwithsyserr (mio, 0, errno, "unable to set FD_CLOEXEC");
 			return -1;
 		}
 	}
@@ -478,6 +487,7 @@ static int dev_sck_make_client (mio_dev_t* dev, void* ctx)
 
 static int dev_sck_kill (mio_dev_t* dev, int force)
 {
+	mio_t* mio = dev->mio;
 	mio_dev_sck_t* rdev = (mio_dev_sck_t*)dev;
 
 	if (IS_STATEFUL(rdev))
@@ -491,14 +501,14 @@ static int dev_sck_kill (mio_dev_t* dev, int force)
 
 		if (rdev->tmrjob_index != MIO_TMRIDX_INVALID)
 		{
-			mio_deltmrjob (dev->mio, rdev->tmrjob_index);
-			MIO_ASSERT (dev->mio, rdev->tmrjob_index == MIO_TMRIDX_INVALID);
+			mio_deltmrjob (mio, rdev->tmrjob_index);
+			MIO_ASSERT (mio, rdev->tmrjob_index == MIO_TMRIDX_INVALID);
 		}
 	}
 	else
 	{
-		MIO_ASSERT (dev->mio, rdev->state == 0);
-		MIO_ASSERT (dev->mio, rdev->tmrjob_index == MIO_TMRIDX_INVALID);
+		MIO_ASSERT (mio, rdev->state == 0);
+		MIO_ASSERT (mio, rdev->tmrjob_index == MIO_TMRIDX_INVALID);
 
 		if (rdev->on_disconnect) rdev->on_disconnect (rdev);
 	}
@@ -519,7 +529,7 @@ static int dev_sck_kill (mio_dev_t* dev, int force)
 
 	if (rdev->sck != MIO_SCKHND_INVALID) 
 	{
-		close_async_socket (rdev->mio, rdev->sck);
+		close_async_socket (mio, rdev->sck);
 		rdev->sck = MIO_SCKHND_INVALID;
 	}
 
@@ -534,6 +544,7 @@ static mio_syshnd_t dev_sck_getsyshnd (mio_dev_t* dev)
 
 static int dev_sck_read_stateful (mio_dev_t* dev, void* buf, mio_iolen_t* len, mio_devaddr_t* srcaddr)
 {
+	mio_t* mio = dev->mio;
 	mio_dev_sck_t* rdev = (mio_dev_sck_t*)dev;
 
 #if defined(USE_SSL)
@@ -541,12 +552,12 @@ static int dev_sck_read_stateful (mio_dev_t* dev, void* buf, mio_iolen_t* len, m
 	{
 		int x;
 
-		x = SSL_read ((SSL*)rdev->ssl, buf, *len);
+		x = SSL_read((SSL*)rdev->ssl, buf, *len);
 		if (x <= -1)
 		{
 			int err = SSL_get_error((SSL*)rdev->ssl, x);
 			if (err == SSL_ERROR_WANT_READ || err == SSL_ERROR_WANT_WRITE) return 0;
-			rdev->mio->errnum = MIO_ESYSERR;
+			set_ssl_error (mio, err);
 			return -1;
 		}
 
@@ -557,12 +568,12 @@ static int dev_sck_read_stateful (mio_dev_t* dev, void* buf, mio_iolen_t* len, m
 #endif
 		ssize_t x;
 
-		x = recv (rdev->sck, buf, *len, 0);
+		x = recv(rdev->sck, buf, *len, 0);
 		if (x == -1)
 		{
 			if (errno == EINPROGRESS || errno == EWOULDBLOCK || errno == EAGAIN) return 0;  /* no data available */
 			if (errno == EINTR) return 0;
-			mio_seterrwithsyserr (rdev->mio, 0, errno);
+			mio_seterrwithsyserr (mio, 0, errno);
 			return -1;
 		}
 
@@ -575,6 +586,7 @@ static int dev_sck_read_stateful (mio_dev_t* dev, void* buf, mio_iolen_t* len, m
 
 static int dev_sck_read_stateless (mio_dev_t* dev, void* buf, mio_iolen_t* len, mio_devaddr_t* srcaddr)
 {
+	mio_t* mio = dev->mio;
 	mio_dev_sck_t* rdev = (mio_dev_sck_t*)dev;
 	mio_scklen_t srcaddrlen;
 	ssize_t x;
@@ -585,7 +597,7 @@ static int dev_sck_read_stateless (mio_dev_t* dev, void* buf, mio_iolen_t* len,
 	{
 		if (errno == EINPROGRESS || errno == EWOULDBLOCK || errno == EAGAIN) return 0;  /* no data available */
 		if (errno == EINTR) return 0;
-		mio_seterrwithsyserr (rdev->mio, 0, errno);
+		mio_seterrwithsyserr (mio, 0, errno);
 		return -1;
 	}
 
@@ -599,6 +611,7 @@ static int dev_sck_read_stateless (mio_dev_t* dev, void* buf, mio_iolen_t* len,
 
 static int dev_sck_write_stateful (mio_dev_t* dev, const void* data, mio_iolen_t* len, const mio_devaddr_t* dstaddr)
 {
+	mio_t* mio = dev->mio;
 	mio_dev_sck_t* rdev = (mio_dev_sck_t*)dev;
 
 #if defined(USE_SSL)
@@ -610,21 +623,20 @@ static int dev_sck_write_stateful (mio_dev_t* dev, const void* data, mio_iolen_t
 		{
 			/* it's a writing finish indicator. close the writing end of
 			 * the socket, probably leaving it in the half-closed state */
-			if (SSL_shutdown ((SSL*)rdev->ssl) == -1)
+			if ((x = SSL_shutdown((SSL*)rdev->ssl)) == -1)
 			{
-				rdev->mio->errnum = MIO_ESYSERR;
+				set_ssl_error (mio, SSL_get_error((SSL*)rdev->ssl, x));
 				return -1;
 			}
-
 			return 1;
 		}
 
-		x = SSL_write ((SSL*)rdev->ssl, data, *len);
+		x = SSL_write((SSL*)rdev->ssl, data, *len);
 		if (x <= -1)
 		{
 			int err = SSL_get_error ((SSL*)rdev->ssl, x);
 			if (err == SSL_ERROR_WANT_READ || err == SSL_ERROR_WANT_WRITE) return 0;
-			rdev->mio->errnum = MIO_ESYSERR;
+			set_ssl_error (mio, err);
 			return -1;
 		}
 
@@ -642,7 +654,7 @@ static int dev_sck_write_stateful (mio_dev_t* dev, const void* data, mio_iolen_t
 			 * the socket, probably leaving it in the half-closed state */
 			if (shutdown(rdev->sck, SHUT_WR) == -1)
 			{
-				mio_seterrwithsyserr (rdev->mio, 0, errno);
+				mio_seterrwithsyserr (mio, 0, errno);
 				return -1;
 			}
 
@@ -658,7 +670,7 @@ static int dev_sck_write_stateful (mio_dev_t* dev, const void* data, mio_iolen_t
 		{
 			if (errno == EINPROGRESS || errno == EWOULDBLOCK || errno == EAGAIN) return 0;  /* no data can be written */
 			if (errno == EINTR) return 0;
-			mio_seterrwithsyserr (rdev->mio, 0, errno);
+			mio_seterrwithsyserr (mio, 0, errno);
 			return -1;
 		}
 
@@ -671,6 +683,7 @@ static int dev_sck_write_stateful (mio_dev_t* dev, const void* data, mio_iolen_t
 
 static int dev_sck_write_stateless (mio_dev_t* dev, const void* data, mio_iolen_t* len, const mio_devaddr_t* dstaddr)
 {
+	mio_t* mio = dev->mio;
 	mio_dev_sck_t* rdev = (mio_dev_sck_t*)dev;
 	ssize_t x;
 
@@ -679,7 +692,7 @@ static int dev_sck_write_stateless (mio_dev_t* dev, const void* data, mio_iolen_
 	{
 		if (errno == EINPROGRESS || errno == EWOULDBLOCK || errno == EAGAIN) return 0;  /* no data can be written */
 		if (errno == EINTR) return 0;
-		mio_seterrwithsyserr (rdev->mio, 0, errno);
+		mio_seterrwithsyserr (mio, 0, errno);
 		return -1;
 	}
 
@@ -691,26 +704,25 @@ static int dev_sck_write_stateless (mio_dev_t* dev, const void* data, mio_iolen_
 
 static int do_ssl (mio_dev_sck_t* dev, int (*ssl_func)(SSL*))
 {
-	int ret;
-	int watcher_cmd;
-	int watcher_events;
+	mio_t* mio = dev->mio;
+	int ret, watcher_cmd, watcher_events;
 
-	MIO_ASSERT (dev->ssl_ctx);
+	MIO_ASSERT (mio, dev->ssl_ctx);
 
 	if (!dev->ssl)
 	{
 		SSL* ssl;
 
-		ssl = SSL_new (dev->ssl_ctx);
+		ssl = SSL_new(dev->ssl_ctx);
 		if (!ssl)
 		{
-			dev->mio->errnum = MIO_ESYSERR;
+			set_ssl_error (mio, ERR_get_error());
 			return -1;
 		}
 
-		if (SSL_set_fd (ssl, dev->sck) == 0)
+		if (SSL_set_fd(ssl, dev->sck) == 0)
 		{
-			dev->mio->errnum = MIO_ESYSERR;
+			set_ssl_error (mio, ERR_get_error());
 			return -1;
 		}
 
@@ -722,10 +734,10 @@ static int do_ssl (mio_dev_sck_t* dev, int (*ssl_func)(SSL*))
 	watcher_cmd = MIO_DEV_WATCH_RENEW;
 	watcher_events = 0;
 
-	ret = ssl_func ((SSL*)dev->ssl);
+	ret = ssl_func((SSL*)dev->ssl);
 	if (ret <= 0)
 	{
-		int err = SSL_get_error (dev->ssl, ret);
+		int err = SSL_get_error(dev->ssl, ret);
 		if (err == SSL_ERROR_WANT_READ)
 		{
 			/* handshaking isn't complete */
@@ -740,7 +752,7 @@ static int do_ssl (mio_dev_sck_t* dev, int (*ssl_func)(SSL*))
 		}
 		else
 		{
-			dev->mio->errnum = MIO_ESYSERR;
+			set_ssl_error (mio, err);
 			ret = -1;
 		}
 	}
@@ -751,7 +763,7 @@ static int do_ssl (mio_dev_sck_t* dev, int (*ssl_func)(SSL*))
 
 	if (mio_dev_watch ((mio_dev_t*)dev, watcher_cmd, watcher_events) <= -1)
 	{
-		mio_stop (dev->mio, MIO_STOPREQ_WATCHER_ERROR);
+		mio_stop (mio, MIO_STOPREQ_WATCHER_ERROR);
 		ret = -1;
 	}
 
@@ -771,8 +783,8 @@ static MIO_INLINE int accept_ssl (mio_dev_sck_t* dev)
 
 static int dev_sck_ioctl (mio_dev_t* dev, int cmd, void* arg)
 {
-	mio_dev_sck_t* rdev = (mio_dev_sck_t*)dev;
 	mio_t* mio = dev->mio;
+	mio_dev_sck_t* rdev = (mio_dev_sck_t*)dev;
 
 	switch (cmd)
 	{
@@ -789,16 +801,16 @@ static int dev_sck_ioctl (mio_dev_t* dev, int cmd, void* arg)
 			if (MIO_DEV_SCK_GET_PROGRESS(rdev))
 			{
 				/* can't bind again */
-				rdev->mio->errnum = MIO_EPERM;
+				mio_seterrbfmt (mio, MIO_EPERM, "operation in progress. not allowed to bind again");
 				return -1;
 			}
 
 			if (bnd->options & MIO_DEV_SCK_BIND_BROADCAST)
 			{
 				int v = 1;
-				if (setsockopt (rdev->sck, SOL_SOCKET, SO_BROADCAST, &v, MIO_SIZEOF(v)) == -1)
+				if (setsockopt(rdev->sck, SOL_SOCKET, SO_BROADCAST, &v, MIO_SIZEOF(v)) == -1)
 				{
-					mio_seterrwithsyserr (rdev->mio, 0, errno);
+					mio_seterrbfmtwithsyserr (mio, 0, errno, "unable to set SO_BROADCAST");
 					return -1;
 				}
 			}
@@ -807,13 +819,13 @@ static int dev_sck_ioctl (mio_dev_t* dev, int cmd, void* arg)
 			{
 			#if defined(SO_REUSEADDR)
 				int v = 1;
-				if (setsockopt (rdev->sck, SOL_SOCKET, SO_REUSEADDR, &v, MIO_SIZEOF(v)) == -1)
+				if (setsockopt(rdev->sck, SOL_SOCKET, SO_REUSEADDR, &v, MIO_SIZEOF(v)) == -1)
 				{
-					mio_seterrwithsyserr (rdev->mio, 0, errno);
+					mio_seterrbfmtwithsyserr (mio, 0, errno, "unable to set SO_REUSEADDR");
 					return -1;
 				}
 			#else
-				rdev->mio->errnum = MIO_ENOIMPL;
+				mio_seterrnum (mio, MIO_ENOIMPL);
 				return -1;
 			#endif
 			}
@@ -822,13 +834,13 @@ static int dev_sck_ioctl (mio_dev_t* dev, int cmd, void* arg)
 			{
 			#if defined(SO_REUSEPORT)
 				int v = 1;
-				if (setsockopt (rdev->sck, SOL_SOCKET, SO_REUSEPORT, &v, MIO_SIZEOF(v)) == -1)
+				if (setsockopt(rdev->sck, SOL_SOCKET, SO_REUSEPORT, &v, MIO_SIZEOF(v)) == -1)
 				{
-					mio_seterrwithsyserr (rdev->mio, 0, errno);
+					mio_seterrbfmtwithsyserr (mio, 0, errno, "unable to set SO_REUSEPORT");
 					return -1;
 				}
 			#else
-				rdev->mio->errnum = MIO_ENOIMPL;
+				mio_seterrnum (mio, MIO_ENOIMPL);
 				return -1;
 			#endif
 			}
@@ -839,11 +851,11 @@ static int dev_sck_ioctl (mio_dev_t* dev, int cmd, void* arg)
 				int v = 1;
 				if (setsockopt(rdev->sck, SOL_IP, IP_TRANSPARENT, &v, MIO_SIZEOF(v)) == -1)
 				{
-					mio_seterrwithsyserr (rdev->mio, 0, errno);
+					mio_seterrbfmtwithsyserr (mio, 0, errno, "unable to set IP_TRANSPARENT");
 					return -1;
 				}
 			#else
-				rdev->mio->errnum = MIO_ENOIMPL;
+				mio_seterrnum (mio, MIO_ENOIMPL);
 				return -1;
 			#endif
 			}
@@ -869,14 +881,14 @@ static int dev_sck_ioctl (mio_dev_t* dev, int cmd, void* arg)
 			#if defined(USE_SSL)
 				if (!bnd->ssl_certfile || !bnd->ssl_keyfile)
 				{
-					rdev->mio->errnum = MIO_EINVAL;
+					mio_seterrbfmt (mio, MIO_EINVAL, "SSL certficate/key file not set");
 					return -1;
 				}
 
 				ssl_ctx = SSL_CTX_new(SSLv23_server_method());
 				if (!ssl_ctx)
 				{
-					rdev->mio->errnum = MIO_ESYSERR;
+					set_ssl_error (mio, ERR_get_error());
 					return -1;
 				}
 
@@ -885,8 +897,8 @@ static int dev_sck_ioctl (mio_dev_t* dev, int cmd, void* arg)
 				    SSL_CTX_check_private_key(ssl_ctx) == 0  /*||
 				    SSL_CTX_use_certificate_chain_file (ssl_ctx, bnd->chainfile) == 0*/)
 				{
+					set_ssl_error (mio, ERR_get_error());
 					SSL_CTX_free (ssl_ctx);
-					rdev->mio->errnum = MIO_ESYSERR;
 					return -1;
 				}
 
@@ -899,17 +911,23 @@ static int dev_sck_ioctl (mio_dev_t* dev, int cmd, void* arg)
 
 				rdev->tmout = bnd->accept_tmout;
 			#else
-				rdev->mio->errnum = MIO_ENOIMPL;
+				mio_seterrnum (mio, MIO_ENOIMPL);
 				return -1;
 			#endif
 			}
 
-			if (mio_getsckaddrinfo(dev->mio, &bnd->localaddr, &sl, &fam) <= -1) return -1;
+			if (mio_getsckaddrinfo(mio, &bnd->localaddr, &sl, &fam) <= -1) 
+			{
+			#if defined(USE_SSL)
+				if (ssl_ctx) SSL_CTX_free (ssl_ctx);
+			#endif
+				return -1;
+			}
 
 			x = bind(rdev->sck, sa, sl);
 			if (x == -1)
 			{
-				mio_seterrwithsyserr (rdev->mio, 0, errno);
+				mio_seterrwithsyserr (mio, 0, errno);
 			#if defined(USE_SSL)
 				if (ssl_ctx) SSL_CTX_free (ssl_ctx);
 			#endif
@@ -939,13 +957,13 @@ static int dev_sck_ioctl (mio_dev_t* dev, int cmd, void* arg)
 			if (MIO_DEV_SCK_GET_PROGRESS(rdev))
 			{
 				/* can't connect again */
-				rdev->mio->errnum = MIO_EPERM;
+				mio_seterrbfmt (mio, MIO_EPERM, "operation in progress. disallowed to connect again");
 				return -1;
 			}
 
 			if (!IS_STATEFUL(rdev)) 
 			{
-				dev->mio->errnum = MIO_ENOCAPA;
+				mio_seterrbfmt (mio, MIO_EPERM, "disallowed to connect stateless device");
 				return -1;
 			}
 
@@ -953,7 +971,7 @@ static int dev_sck_ioctl (mio_dev_t* dev, int cmd, void* arg)
 			else if (sa->sa_family == AF_INET6) sl = MIO_SIZEOF(struct sockaddr_in6);
 			else 
 			{
-				dev->mio->errnum = MIO_EINVAL;
+				mio_seterrbfmt (mio, MIO_EINVAL, "unknown address family %d", sa->sa_family);
 				return -1;
 			}
 
@@ -975,7 +993,7 @@ static int dev_sck_ioctl (mio_dev_t* dev, int cmd, void* arg)
 				ssl_ctx = SSL_CTX_new(SSLv23_client_method());
 				if (!ssl_ctx)
 				{
-					rdev->mio->errnum = MIO_ESYSERR;
+					set_ssl_error (mio, ERR_get_error());
 					return -1;
 				}
 
@@ -1003,7 +1021,7 @@ fcntl (rdev->sck, F_SETFL, flags | O_NONBLOCK);
 					if (mio_dev_watch((mio_dev_t*)rdev, MIO_DEV_WATCH_UPDATE, MIO_DEV_EVENT_IN | MIO_DEV_EVENT_OUT) <= -1)
 					{
 						/* watcher update failure. it's critical */
-						mio_stop (rdev->mio, MIO_STOPREQ_WATCHER_ERROR);
+						mio_stop (mio, MIO_STOPREQ_WATCHER_ERROR);
 						goto oops_connect;
 					}
 					else
@@ -1020,7 +1038,7 @@ fcntl (rdev->sck, F_SETFL, flags | O_NONBLOCK);
 							{
 								/* update rdev->tmout to the deadline of the connect timeout job */
 								MIO_ASSERT (mio, rdev->tmrjob_index != MIO_TMRIDX_INVALID);
-								mio_gettmrjobdeadline (rdev->mio, rdev->tmrjob_index, &rdev->tmout);
+								mio_gettmrjobdeadline (mio, rdev->tmrjob_index, &rdev->tmout);
 							}
 						}
 
@@ -1033,13 +1051,13 @@ fcntl (rdev->sck, F_SETFL, flags | O_NONBLOCK);
 					}
 				}
 
-				mio_seterrwithsyserr (rdev->mio, 0, errno);
+				mio_seterrwithsyserr (mio, 0, errno);
 
 			oops_connect:
 				if (mio_dev_watch((mio_dev_t*)rdev, MIO_DEV_WATCH_UPDATE, MIO_DEV_EVENT_IN) <= -1)
 				{
 					/* watcher update failure. it's critical */
-					mio_stop (rdev->mio, MIO_STOPREQ_WATCHER_ERROR);
+					mio_stop (mio, MIO_STOPREQ_WATCHER_ERROR);
 				}
 
 			#if defined(USE_SSL)
@@ -1067,12 +1085,12 @@ fcntl (rdev->sck, F_SETFL, flags | O_NONBLOCK);
 						SSL_CTX_free (rdev->ssl_ctx);
 						rdev->ssl_ctx = MIO_NULL;
 
-						MIO_ASSERT (rdev->ssl == MIO_NULL);
+						MIO_ASSERT (mio, rdev->ssl == MIO_NULL);
 						return -1;
 					}
 					if (x == 0) 
 					{
-						MIO_ASSERT (rdev->tmrjob_index == MIO_TMRIDX_INVALID);
+						MIO_ASSERT (mio, rdev->tmrjob_index == MIO_TMRIDX_INVALID);
 						MIO_INIT_NTIME (&rdev->tmout, 0, 0); /* just in case */
 
 						/* it's ok to use conn->connect_tmout for ssl-connect as
@@ -1087,14 +1105,14 @@ fcntl (rdev->sck, F_SETFL, flags | O_NONBLOCK);
 								SSL_CTX_free (rdev->ssl_ctx);
 								rdev->ssl_ctx = MIO_NULL;
 
-								MIO_ASSERT (rdev->ssl == MIO_NULL);
+								MIO_ASSERT (mio, rdev->ssl == MIO_NULL);
 								return -1;
 							}
 							else
 							{
 								/* update rdev->tmout to the deadline of the connect timeout job */
-								MIO_ASSERT (rdev->tmrjob_index != MIO_TMRIDX_INVALID);
-								mio_gettmrjobdeadline (rdev->mio, rdev->tmrjob_index, &rdev->tmout);
+								MIO_ASSERT (mio, rdev->tmrjob_index != MIO_TMRIDX_INVALID);
+								mio_gettmrjobdeadline (mio, rdev->tmrjob_index, &rdev->tmout);
 							}
 						}
 
@@ -1126,20 +1144,20 @@ fcntl (rdev->sck, F_SETFL, flags | O_NONBLOCK);
 			if (MIO_DEV_SCK_GET_PROGRESS(rdev))
 			{
 				/* can't listen again */
-				rdev->mio->errnum = MIO_EPERM;
+				mio_seterrbfmt (mio, MIO_EPERM, "operation in progress. disallowed to listen again");
 				return -1;
 			}
 
 			if (!IS_STATEFUL(rdev)) 
 			{
-				dev->mio->errnum = MIO_ENOCAPA;
+				mio_seterrbfmt (mio, MIO_EPERM, "disallowed to listen on stateless device");
 				return -1;
 			}
 
 			x = listen (rdev->sck, lstn->backlogs);
 			if (x == -1) 
 			{
-				mio_seterrwithsyserr (rdev->mio, 0, errno);
+				mio_seterrwithsyserr (mio, 0, errno);
 				return -1;
 			}
 
@@ -1188,15 +1206,17 @@ static mio_dev_mth_t dev_mth_clisck =
 
 static int harvest_outgoing_connection (mio_dev_sck_t* rdev)
 {
+	mio_t* mio = rdev->mio;
 	int errcode;
 	mio_scklen_t len;
+	
 
-	MIO_ASSERT (rdev->mio, !(rdev->state & MIO_DEV_SCK_CONNECTED));
+	MIO_ASSERT (mio, !(rdev->state & MIO_DEV_SCK_CONNECTED));
 
 	len = MIO_SIZEOF(errcode);
 	if (getsockopt(rdev->sck, SOL_SOCKET, SO_ERROR, (char*)&errcode, &len) == -1)
 	{
-		mio_seterrwithsyserr (rdev->mio, 0, errno);
+		mio_seterrbfmtwithsyserr (mio, 0, errno, "unable to get SO_ERROR");
 		return -1;
 	}
 	else if (errcode == 0)
@@ -1208,8 +1228,8 @@ static int harvest_outgoing_connection (mio_dev_sck_t* rdev)
 
 		if (rdev->tmrjob_index != MIO_TMRIDX_INVALID)
 		{
-			mio_deltmrjob (rdev->mio, rdev->tmrjob_index);
-			MIO_ASSERT (rdev->mio, rdev->tmrjob_index == MIO_TMRIDX_INVALID);
+			mio_deltmrjob (mio, rdev->tmrjob_index);
+			MIO_ASSERT (mio, rdev->tmrjob_index == MIO_TMRIDX_INVALID);
 		}
 
 		addrlen = MIO_SIZEOF(localaddr);
@@ -1218,7 +1238,7 @@ static int harvest_outgoing_connection (mio_dev_sck_t* rdev)
 		if (mio_dev_watch((mio_dev_t*)rdev, MIO_DEV_WATCH_RENEW, 0) <= -1) 
 		{
 			/* watcher update failure. it's critical */
-			mio_stop (rdev->mio, MIO_STOPREQ_WATCHER_ERROR);
+			mio_stop (mio, MIO_STOPREQ_WATCHER_ERROR);
 			return -1;
 		}
 
@@ -1226,7 +1246,7 @@ static int harvest_outgoing_connection (mio_dev_sck_t* rdev)
 		if (rdev->ssl_ctx)
 		{
 			int x;
-			MIO_ASSERT (!rdev->ssl); /* must not be SSL-connected yet */
+			MIO_ASSERT (mio, !rdev->ssl); /* must not be SSL-connected yet */
 
 			x = connect_ssl (rdev);
 			if (x <= -1) return -1;
@@ -1235,7 +1255,7 @@ static int harvest_outgoing_connection (mio_dev_sck_t* rdev)
 				/* underlying socket connected but not SSL-connected */
 				MIO_DEV_SCK_SET_PROGRESS (rdev, MIO_DEV_SCK_CONNECTING_SSL);
 
-				MIO_ASSERT (rdev->tmrjob_index == MIO_TMRIDX_INVALID);
+				MIO_ASSERT (mio, rdev->tmrjob_index == MIO_TMRIDX_INVALID);
 
 				/* rdev->tmout has been set to the deadline of the connect task
 				 * when the CONNECT IOCTL command has been executed. use the 
@@ -1272,7 +1292,7 @@ static int harvest_outgoing_connection (mio_dev_sck_t* rdev)
 	}
 	else
 	{
-		mio_seterrwithsyserr (rdev->mio, 0, errcode);
+		mio_seterrwithsyserr (mio, 0, errcode);
 		return -1;
 	}
 }
@@ -1300,7 +1320,7 @@ static int accept_incoming_connection (mio_dev_sck_t* rdev)
 			if (errno == EINPROGRESS || errno == EWOULDBLOCK || errno == EAGAIN) return 0;
 			if (errno == EINTR) return 0; /* if interrupted by a signal, treat it as if it's EINPROGRESS */
 
-			mio_seterrwithsyserr (rdev->mio, 0, errno);
+			mio_seterrwithsyserr (mio, 0, errno);
 			return -1;
 		 }
 
@@ -1319,7 +1339,7 @@ static int accept_incoming_connection (mio_dev_sck_t* rdev)
 		if (errno == EINPROGRESS || errno == EWOULDBLOCK || errno == EAGAIN) return 0;
 		if (errno == EINTR) return 0; /* if interrupted by a signal, treat it as if it's EINPROGRESS */
 
-		mio_seterrwithsyserr (rdev->mio, 0, errno);
+		mio_seterrwithsyserr (mio, 0, errno);
 		return -1;
 	}
 
@@ -1329,7 +1349,7 @@ 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(rdev->mio, rdev->dev_size, &dev_mth_clisck, rdev->dev_evcb, &clisck); 
+	clidev = (mio_dev_sck_t*)mio_makedev(mio, rdev->dev_size, &dev_mth_clisck, rdev->dev_evcb, &clisck); 
 	if (!clidev) 
 	{
 		close (clisck);
@@ -1350,12 +1370,12 @@ accept_done:
 	 * the address of the local socket. In this case, it should
 	 * be same as the result of getsockname(). */
 	addrlen = MIO_SIZEOF(clidev->orgdstaddr);
-	if (getsockopt (clisck, SOL_IP, SO_ORIGINAL_DST, &clidev->orgdstaddr, &addrlen) == -1) clidev->orgdstaddr = rdev->localaddr;
+	if (getsockopt(clisck, SOL_IP, SO_ORIGINAL_DST, &clidev->orgdstaddr, &addrlen) == -1) clidev->orgdstaddr = rdev->localaddr;
 #else
 	clidev->orgdstaddr = rdev->localaddr;
 #endif
 
-	if (!mio_equalsckaddrs (rdev->mio, &clidev->orgdstaddr, &clidev->localaddr))
+	if (!mio_equalsckaddrs (mio, &clidev->orgdstaddr, &clidev->localaddr))
 	{
 		clidev->state |= MIO_DEV_SCK_INTERCEPTED;
 	}
@@ -1419,6 +1439,7 @@ accept_done:
 
 static int dev_evcb_sck_ready_stateful (mio_dev_t* dev, int events)
 {
+	mio_t* mio = dev->mio;
 	mio_dev_sck_t* rdev = (mio_dev_sck_t*)dev;
 
 	if (events & MIO_DEV_EVENT_ERR)
@@ -1427,17 +1448,17 @@ static int dev_evcb_sck_ready_stateful (mio_dev_t* dev, int events)
 		mio_scklen_t len;
 
 		len = MIO_SIZEOF(errcode);
-		if (getsockopt (rdev->sck, SOL_SOCKET, SO_ERROR, (char*)&errcode, &len) == -1)
+		if (getsockopt(rdev->sck, SOL_SOCKET, SO_ERROR, (char*)&errcode, &len) == -1)
 		{
 			/* the error number is set to the socket error code.
 			 * errno resulting from getsockopt() doesn't reflect the actual
 			 * socket error. so errno is not used to set the error number.
 			 * instead, the generic device error MIO_EDEVERRR is used */
-			rdev->mio->errnum = MIO_EDEVERR;
+			mio_seterrbfmt (mio, MIO_EDEVERR, "device error - unable to get SO_ERROR");
 		}
 		else
 		{
-			mio_seterrwithsyserr (rdev->mio, 0, errcode);
+			mio_seterrwithsyserr (mio, 0, errcode);
 		}
 		return -1;
 	}
@@ -1449,19 +1470,19 @@ static int dev_evcb_sck_ready_stateful (mio_dev_t* dev, int events)
 			if (events & MIO_DEV_EVENT_HUP)
 			{
 				/* device hang-up */
-				rdev->mio->errnum = MIO_EDEVHUP;
+				mio_seterrnum (mio, MIO_EDEVHUP);
 				return -1;
 			}
 			else if (events & (MIO_DEV_EVENT_PRI | MIO_DEV_EVENT_IN))
 			{
 				/* invalid event masks. generic device error */
-				rdev->mio->errnum = MIO_EDEVERR;
+				mio_seterrbfmt (mio, MIO_EDEVERR, "device error - invalid event mask");
 				return -1;
 			}
 			else if (events & MIO_DEV_EVENT_OUT)
 			{
 				/* when connected, the socket becomes writable */
-				return harvest_outgoing_connection (rdev);
+				return harvest_outgoing_connection(rdev);
 			}
 			else
 			{
@@ -1473,20 +1494,20 @@ static int dev_evcb_sck_ready_stateful (mio_dev_t* dev, int events)
 			if (events & MIO_DEV_EVENT_HUP)
 			{
 				/* device hang-up */
-				rdev->mio->errnum = MIO_EDEVHUP;
+				mio_seterrnum (mio, MIO_EDEVHUP);
 				return -1;
 			}
 			else if (events & MIO_DEV_EVENT_PRI)
 			{
 				/* invalid event masks. generic device error */
-				rdev->mio->errnum = MIO_EDEVERR;
+				mio_seterrbfmt (mio, MIO_EDEVERR, "device error - invalid event mask");
 				return -1;
 			}
 			else if (events & (MIO_DEV_EVENT_IN | MIO_DEV_EVENT_OUT))
 			{
 				int x;
 
-				x = connect_ssl (rdev);
+				x = connect_ssl(rdev);
 				if (x <= -1) return -1;
 				if (x == 0) return 0; /* not SSL-Connected */
 
@@ -1505,7 +1526,7 @@ static int dev_evcb_sck_ready_stateful (mio_dev_t* dev, int events)
 				return 0; /* success. no actual I/O yet */
 			}
 		#else
-			rdev->mio->errnum = MIO_EINTERN;
+			mio_seterrnum (mio, MIO_EINTERN);
 			return -1;
 		#endif
 
@@ -1514,12 +1535,12 @@ static int dev_evcb_sck_ready_stateful (mio_dev_t* dev, int events)
 			if (events & MIO_DEV_EVENT_HUP)
 			{
 				/* device hang-up */
-				rdev->mio->errnum = MIO_EDEVHUP;
+				mio_seterrnum (mio, MIO_EDEVHUP);
 				return -1;
 			}
 			else if (events & (MIO_DEV_EVENT_PRI | MIO_DEV_EVENT_OUT))
 			{
-				rdev->mio->errnum = MIO_EDEVERR;
+				mio_seterrbfmt (mio, MIO_EDEVERR, "device error - invalid event mask");
 				return -1;
 			}
 			else if (events & MIO_DEV_EVENT_IN)
@@ -1536,19 +1557,19 @@ static int dev_evcb_sck_ready_stateful (mio_dev_t* dev, int events)
 			if (events & MIO_DEV_EVENT_HUP)
 			{
 				/* device hang-up */
-				rdev->mio->errnum = MIO_EDEVHUP;
+				mio_seterrnum (mio, MIO_EDEVHUP);
 				return -1;
 			}
 			else if (events & MIO_DEV_EVENT_PRI)
 			{
 				/* invalid event masks. generic device error */
-				rdev->mio->errnum = MIO_EDEVERR;
+				mio_seterrbfmt (mio, MIO_EDEVERR, "device error - invalid event mask");
 				return -1;
 			}
 			else if (events & (MIO_DEV_EVENT_IN | MIO_DEV_EVENT_OUT))
 			{
 				int x;
-				x = accept_ssl (rdev);
+				x = accept_ssl(rdev);
 				if (x <= -1) return -1;
 				if (x <= 0) return 0; /* not SSL-accepted yet */
 
@@ -1569,7 +1590,7 @@ static int dev_evcb_sck_ready_stateful (mio_dev_t* dev, int events)
 				return 0; /* no reading or writing yet */
 			}
 		#else
-			rdev->mio->errnum = MIO_EINTERN;
+			mio_seterrnum (mio, MIO_EINTERN);
 			return -1;
 		#endif
 
@@ -1583,7 +1604,7 @@ static int dev_evcb_sck_ready_stateful (mio_dev_t* dev, int events)
 					return 1;
 				}
 
-				rdev->mio->errnum = MIO_EDEVHUP;
+				mio_seterrnum (mio, MIO_EDEVHUP);
 				return -1;
 			}
 
@@ -1593,6 +1614,7 @@ static int dev_evcb_sck_ready_stateful (mio_dev_t* dev, int events)
 
 static int dev_evcb_sck_ready_stateless (mio_dev_t* dev, int events)
 {
+	mio_t* mio = dev->mio;
 	mio_dev_sck_t* rdev = (mio_dev_sck_t*)dev;
 
 	if (events & MIO_DEV_EVENT_ERR)
@@ -1607,7 +1629,7 @@ static int dev_evcb_sck_ready_stateless (mio_dev_t* dev, int events)
 			 * errno resulting from getsockopt() doesn't reflect the actual
 			 * socket error. so errno is not used to set the error number.
 			 * instead, the generic device error MIO_EDEVERRR is used */
-			rdev->mio->errnum = MIO_EDEVERR;
+			mio_seterrbfmt (mio, MIO_EDEVERR, "device error - unable to get SO_ERROR");
 		}
 		else
 		{
@@ -1617,7 +1639,7 @@ static int dev_evcb_sck_ready_stateless (mio_dev_t* dev, int events)
 	}
 	else if (events & MIO_DEV_EVENT_HUP)
 	{
-		rdev->mio->errnum = MIO_EDEVHUP;
+		mio_seterrnum (mio, MIO_EDEVHUP);
 		return -1;
 	}
 
@@ -1627,25 +1649,25 @@ static int dev_evcb_sck_ready_stateless (mio_dev_t* dev, int events)
 static int dev_evcb_sck_on_read_stateful (mio_dev_t* dev, const void* data, mio_iolen_t dlen, const mio_devaddr_t* srcaddr)
 {
 	mio_dev_sck_t* rdev = (mio_dev_sck_t*)dev;
-	return rdev->on_read (rdev, data, dlen, MIO_NULL);
+	return rdev->on_read(rdev, data, dlen, MIO_NULL);
 }
 
 static int dev_evcb_sck_on_write_stateful (mio_dev_t* dev, mio_iolen_t wrlen, void* wrctx, const mio_devaddr_t* dstaddr)
 {
 	mio_dev_sck_t* rdev = (mio_dev_sck_t*)dev;
-	return rdev->on_write (rdev, wrlen, wrctx, MIO_NULL);
+	return rdev->on_write(rdev, wrlen, wrctx, MIO_NULL);
 }
 
 static int dev_evcb_sck_on_read_stateless (mio_dev_t* dev, const void* data, mio_iolen_t dlen, const mio_devaddr_t* srcaddr)
 {
 	mio_dev_sck_t* rdev = (mio_dev_sck_t*)dev;
-	return rdev->on_read (rdev, data, dlen, srcaddr->ptr);
+	return rdev->on_read(rdev, data, dlen, srcaddr->ptr);
 }
 
 static int dev_evcb_sck_on_write_stateless (mio_dev_t* dev, mio_iolen_t wrlen, void* wrctx, const mio_devaddr_t* dstaddr)
 {
 	mio_dev_sck_t* rdev = (mio_dev_sck_t*)dev;
-	return rdev->on_write (rdev, wrlen, wrctx, dstaddr->ptr);
+	return rdev->on_write(rdev, wrlen, wrctx, dstaddr->ptr);
 }
 
 static mio_dev_evcb_t dev_sck_event_callbacks_stateful =
@@ -1670,7 +1692,7 @@ mio_dev_sck_t* mio_dev_sck_make (mio_t* mio, mio_oow_t xtnsize, const mio_dev_sc
 
 	if (info->type < 0 && info->type >= MIO_COUNTOF(sck_type_map))
 	{
-		mio->errnum = MIO_EINVAL;
+		mio_seterrnum (mio, MIO_EINVAL);
 		return MIO_NULL;
 	}
 
diff --git a/mio/lib/mio.c b/mio/lib/mio.c
index 97f058b..5c2c532 100644
--- a/mio/lib/mio.c
+++ b/mio/lib/mio.c
@@ -105,12 +105,12 @@ int mio_init (mio_t* mio, mio_mmgr_t* mmgr, mio_cmgr_t* cmgr, mio_oow_t tmrcapa)
 	if (!mio->log.ptr) goto oops;
 
 	/* inititalize the system-side logging */
-	mio_sys_initlog (mio);
+	if (mio_sys_initlog (mio) <= -1) goto oops;
 	sys_log_inited = 1;
 
 	/* intialize the multiplexer object */
 	if (mio_sys_initmux(mio) <= -1) goto oops;
-	sys_mux_inited = 0;
+	sys_mux_inited = 1;
 
 	/* initialize the timer object */
 	if (tmrcapa <= 0) tmrcapa = 1;
@@ -150,7 +150,7 @@ void mio_fini (mio_t* mio)
 		while ((cwq = mio->cwqfl[i]))
 		{
 			mio->cwqfl[i] = cwq->next;
-			MIO_MMGR_FREE (mio->mmgr, cwq);
+			mio_freemem (mio, cwq);
 		}
 	}
 
@@ -201,10 +201,12 @@ void mio_fini (mio_t* mio)
 
 	/* purge scheduled timer jobs and kill the timer */
 	mio_cleartmrjobs (mio);
-	MIO_MMGR_FREE (mio->mmgr, mio->tmr.jobs);
+	mio_freemem (mio, mio->tmr.jobs);
 
 	mio_sys_finimux (mio); /* close the multiplexer */
 	mio_sys_finilog (mio); /* close the system logger */
+
+	mio_freemem (mio, mio->log.ptr);
 }
 
 int mio_setoption (mio_t* mio, mio_option_t id, const void* value)
@@ -224,7 +226,6 @@ int mio_setoption (mio_t* mio, mio_option_t id, const void* value)
 			return 0;
 	}
 
-einval:
 	mio_seterrnum (mio, MIO_EINVAL);
 	return -1;
 }
@@ -358,7 +359,7 @@ static MIO_INLINE void handle_event (mio_t* mio, mio_dev_t* dev, int events, int
 
 					unlink_wq (mio, q);
 					y = dev->dev_evcb->on_write(dev, q->olen, q->ctx, &q->dstaddr);
-					MIO_MMGR_FREE (mio->mmgr, q);
+					mio_freemem (mio, q);
 
 					if (y <= -1)
 					{
@@ -375,7 +376,7 @@ static MIO_INLINE void handle_event (mio_t* mio, mio_dev_t* dev, int events, int
 						{
 							q = MIO_WQ_HEAD(&dev->wq);
 							unlink_wq (mio, q);
-							MIO_MMGR_FREE (dev->mio->mmgr, q);
+							mio_freemem (mio, q);
 						}
 						break;
 					}
@@ -563,7 +564,7 @@ static MIO_INLINE int __exec (mio_t* mio)
 		else
 		{
 			/* TODO: more reuse of objects of different size? */
-			MIO_MMGR_FREE (mio->mmgr, cwq);
+			mio_freemem (mio, cwq);
 		}
 	}
 
@@ -640,14 +641,9 @@ mio_dev_t* mio_makedev (mio_t* mio, mio_oow_t dev_size, mio_dev_mth_t* dev_mth,
 		return MIO_NULL;
 	}
 
-	dev = MIO_MMGR_ALLOC(mio->mmgr, dev_size);
-	if (!dev)
-	{
-		mio->errnum = MIO_ESYSMEM;
-		return MIO_NULL;
-	}
+	dev = mio_callocmem(mio, dev_size);
+	if (!dev) return MIO_NULL;
 
-	MIO_MEMSET (dev, 0, dev_size);
 	dev->mio = mio;
 	dev->dev_size = dev_size;
 	/* default capability. dev->dev_mth->make() can change this.
@@ -661,10 +657,10 @@ mio_dev_t* mio_makedev (mio_t* mio, mio_oow_t dev_size, mio_dev_mth_t* dev_mth,
 	dev->cw_count = 0;
 
 	/* call the callback function first */
-	mio->errnum = MIO_ENOERR;
+	mio_seterrnum (mio, MIO_ENOERR);
 	if (dev->dev_mth->make(dev, make_ctx) <= -1)
 	{
-		if (mio->errnum == MIO_ENOERR) mio->errnum = MIO_EDEVMAKE;
+		if (mio->errnum == MIO_ENOERR) mio_seterrnum (mio, MIO_EDEVMAKE);
 		goto oops;
 	}
 
@@ -723,18 +719,17 @@ oops_after_make:
 	}
 
 oops:
-	MIO_MMGR_FREE (mio->mmgr, dev);
+	mio_freemem (mio, dev);
 	return MIO_NULL;
 }
 
 static int kill_and_free_device (mio_dev_t* dev, int force)
 {
-	mio_t* mio;
+	mio_t* mio = dev->mio;
 
 	MIO_ASSERT (mio, !(dev->dev_capa & MIO_DEV_CAPA_ACTIVE));
 	MIO_ASSERT (mio, !(dev->dev_capa & MIO_DEV_CAPA_HALTED));
 
-	mio = dev->mio;
 
 	if (dev->dev_mth->kill(dev, force) <= -1) 
 	{
@@ -757,7 +752,7 @@ free_device:
 		dev->dev_capa &= ~MIO_DEV_CAPA_ZOMBIE;
 	}
 
-	MIO_MMGR_FREE (mio->mmgr, dev);
+	mio_freemem (mio, dev);
 	return 0;
 }
 
@@ -833,7 +828,7 @@ void mio_killdev (mio_t* mio, mio_dev_t* dev)
 			if (cwq->dev == dev)
 			{
 				MIO_CWQ_UNLINK (cwq);
-				MIO_MMGR_FREE (mio->mmgr, cwq);
+				mio_freemem (mio, cwq);
 			}
 			cwq = next;
 		}
@@ -845,7 +840,7 @@ void mio_killdev (mio_t* mio, mio_dev_t* dev)
 		mio_wq_t* q;
 		q = MIO_WQ_HEAD(&dev->wq);
 		unlink_wq (mio, q);
-		MIO_MMGR_FREE (mio->mmgr, q);
+		mio_freemem (mio, q);
 	}
 
 	if (dev->dev_capa & MIO_DEV_CAPA_HALTED)
@@ -888,12 +883,10 @@ kill_device:
 
 void mio_dev_halt (mio_dev_t* dev)
 {
+	mio_t* mio = dev->mio;
+
 	if (dev->dev_capa & MIO_DEV_CAPA_ACTIVE)
 	{
-		mio_t* mio;
-
-		mio = dev->mio;
-
 		/* delink the device object from the active device list */
 		UNLINK_DEVICE_FROM_LIST (&mio->actdev, dev);
 		dev->dev_capa &= ~MIO_DEV_CAPA_ACTIVE;
@@ -906,9 +899,15 @@ void mio_dev_halt (mio_dev_t* dev)
 
 int mio_dev_ioctl (mio_dev_t* dev, int cmd, void* arg)
 {
-	if (dev->dev_mth->ioctl) return dev->dev_mth->ioctl (dev, cmd, arg);
-	dev->mio->errnum = MIO_ENOIMPL; /* TODO: different error code ? */
-	return -1;
+	mio_t* mio = dev->mio;
+
+	if (MIO_UNLIKELY(!dev->dev_mth->ioctl))
+	{
+		mio_seterrnum (mio, MIO_ENOIMPL);  /* TODO: different error code ? */
+		return -1;
+	}
+
+	return dev->dev_mth->ioctl(dev, cmd, arg);
 }
 
 int mio_dev_watch (mio_dev_t* dev, mio_dev_watch_cmd_t cmd, int events)
@@ -1108,13 +1107,14 @@ static void on_write_timeout (mio_t* mio, const mio_ntime_t* now, mio_tmrjob_t*
 
 	MIO_ASSERT (mio, q->tmridx == MIO_TMRIDX_INVALID);
 	MIO_WQ_UNLINK(q);
-	MIO_MMGR_FREE (mio->mmgr, q);
+	mio_freemem (mio, q);
 
 	if (x <= -1) mio_dev_halt (dev);
 }
 
 static int __dev_write (mio_dev_t* dev, const void* data, mio_iolen_t len, const mio_ntime_t* tmout, void* wrctx, const mio_devaddr_t* dstaddr)
 {
+	mio_t* mio = dev->mio;
 	const mio_uint8_t* uptr;
 	mio_iolen_t urem, ulen;
 	mio_wq_t* q;
@@ -1124,7 +1124,7 @@ static int __dev_write (mio_dev_t* dev, const void* data, mio_iolen_t len, const
 
 	if (dev->dev_capa & MIO_DEV_CAPA_OUT_CLOSED)
 	{
-		dev->mio->errnum = MIO_ENOCAPA;
+		mio_seterrbfmt (mio, MIO_ENOCAPA, "unable to write to closed device");
 		return -1;
 	}
 
@@ -1181,7 +1181,7 @@ static int __dev_write (mio_dev_t* dev, const void* data, mio_iolen_t len, const
 	{
 		ulen = urem;
 
-		x = dev->dev_mth->write (dev, data, &ulen, dstaddr);
+		x = dev->dev_mth->write(dev, data, &ulen, dstaddr);
 		if (x <= -1) return -1;
 		else if (x == 0) goto enqueue_data;
 
@@ -1204,12 +1204,8 @@ enqueue_data:
 	}
 
 	/* queue the remaining data*/
-	q = (mio_wq_t*)MIO_MMGR_ALLOC(dev->mio->mmgr, MIO_SIZEOF(*q) + (dstaddr? dstaddr->len: 0) + urem);
-	if (!q)
-	{
-		dev->mio->errnum = MIO_ESYSMEM;
-		return -1;
-	}
+	q = (mio_wq_t*)mio_allocmem(mio, MIO_SIZEOF(*q) + (dstaddr? dstaddr->len: 0) + urem);
+	if (!q) return -1;
 
 	q->tmridx = MIO_TMRIDX_INVALID;
 	q->dev = dev;
@@ -1242,10 +1238,10 @@ enqueue_data:
 		tmrjob.handler = on_write_timeout;
 		tmrjob.idxptr = &q->tmridx;
 
-		q->tmridx = mio_instmrjob(dev->mio, &tmrjob);
+		q->tmridx = mio_instmrjob(mio, &tmrjob);
 		if (q->tmridx == MIO_TMRIDX_INVALID) 
 		{
-			MIO_MMGR_FREE (dev->mio->mmgr, q);
+			mio_freemem (mio, q);
 			return -1;
 		}
 	}
@@ -1256,8 +1252,8 @@ enqueue_data:
 		/* if output is not being watched, arrange to do so */
 		if (mio_dev_watch(dev, MIO_DEV_WATCH_RENEW, 0) <= -1)
 		{
-			unlink_wq (dev->mio, q);
-			MIO_MMGR_FREE (dev->mio->mmgr, q);
+			unlink_wq (mio, q);
+			mio_freemem (mio, q);
 			return -1;
 		}
 	}
@@ -1274,7 +1270,7 @@ enqueue_completed_write:
 	cwq_extra_aligned = MIO_ALIGN_POW2(cwq_extra_aligned, MIO_CWQFL_ALIGN);
 	cwqfl_index = cwq_extra_aligned / MIO_CWQFL_SIZE;
 
-	if (cwqfl_index < MIO_COUNTOF(dev->mio->cwqfl) && dev->mio->cwqfl[cwqfl_index])
+	if (cwqfl_index < MIO_COUNTOF(mio->cwqfl) && mio->cwqfl[cwqfl_index])
 	{
 		/* take an available cwq object from the free cwq list */
 		cwq = dev->mio->cwqfl[cwqfl_index];
@@ -1282,12 +1278,8 @@ enqueue_completed_write:
 	}
 	else
 	{
-		cwq = (mio_cwq_t*)MIO_MMGR_ALLOC(dev->mio->mmgr, MIO_SIZEOF(*cwq) + cwq_extra_aligned);
-		if (!cwq)
-		{
-			dev->mio->errnum = MIO_ESYSMEM;
-			return -1;
-		}
+		cwq = (mio_cwq_t*)mio_allocmem(mio, MIO_SIZEOF(*cwq) + cwq_extra_aligned);
+		if (!cwq) return -1;
 	}
 
 	MIO_MEMSET (cwq, 0, MIO_SIZEOF(*cwq));
@@ -1335,7 +1327,7 @@ int mio_makesyshndasync (mio_t* mio, mio_syshnd_t hnd)
 
 	return 0;
 #else
-	mio->errnum = MIO_ENOIMPL;
+	mio_seterrnum (mio, MIO_ENOIMPL);
 	return -1;
 #endif
 }
diff --git a/mio/lib/mio.h b/mio/lib/mio.h
index d8726f6..45bbe23 100644
--- a/mio/lib/mio.h
+++ b/mio/lib/mio.h
@@ -976,6 +976,31 @@ MIO_EXPORT mio_bch_t* mio_dupbchars (
 	mio_oow_t        bcslen
 );
 
+
+/* =========================================================================
+ * MIO VM LOGGING
+ * ========================================================================= */
+
+MIO_EXPORT mio_ooi_t mio_logbfmt (
+	mio_t*           mio,
+	mio_bitmask_t    mask,
+	const mio_bch_t* fmt,
+	...
+);
+
+MIO_EXPORT mio_ooi_t mio_logufmt (
+	mio_t*            mio,
+	mio_bitmask_t     mask,
+	const mio_uch_t*  fmt,
+	...
+);
+ 
+#if defined(MIO_OOCH_IS_UCH)
+#	define mio_logoofmt mio_logufmt
+#else
+#	define mio_logoofmt mio_logbfmt
+#endif
+
 /* =========================================================================
  * MISCELLANEOUS HELPER FUNCTIONS
  * ========================================================================= */
diff --git a/mio/lib/sck-addr.h b/mio/lib/sck-addr.h
index 30e4c8f..011b88d 100644
--- a/mio/lib/sck-addr.h
+++ b/mio/lib/sck-addr.h
@@ -344,7 +344,7 @@ TODO
 					const char_t* stmp = p;
 					unsigned int index;
 					do p++; while (p < end);
-					if (mio_nwifwcsntoindex (stmp, p - stmp, &index) <= -1) return -1;
+					if (mio_nwifwcsntoindex(stmp, p - stmp, &index) <= -1) return -1;
 					nwad->in6.sin6_scope_id = index;
 #endif
 				}
diff --git a/mio/lib/sys-ass.c b/mio/lib/sys-ass.c
index 4aa5562..f66f22b 100644
--- a/mio/lib/sys-ass.c
+++ b/mio/lib/sys-ass.c
@@ -71,6 +71,8 @@
 #	include <sys/types.h>
 #	include <unistd.h>
 #	include <errno.h>
+#	include <signal.h>
+#	include <stdlib.h>
 #endif
 
 #if defined(MIO_BUILD_RELEASE)
diff --git a/mio/lib/sys-log.c b/mio/lib/sys-log.c
index 736b9e6..aef6940 100644
--- a/mio/lib/sys-log.c
+++ b/mio/lib/sys-log.c
@@ -81,21 +81,18 @@
 
 struct mio_sys_log_t
 {
+	int fd;
+	int fd_flag; /* bitwise OR'ed fo logfd_flag_t bits */
+
 	struct
 	{
-		int fd;
-		int fd_flag; /* bitwise OR'ed fo logfd_flag_t bits */
-
-		struct
-		{
-			mio_bch_t buf[4096];
-			mio_oow_t len;
-		} out;
-	} log;
+		mio_bch_t buf[4096];
+		mio_oow_t len;
+	} out;
 };
 
 typedef mio_sys_log_t xtn_t;
-#define GET_XTN(mio) (&(mio)->sys.log)
+#define GET_XTN(mio) ((mio)->sys.log)
 
 
 enum logfd_flag_t
@@ -140,27 +137,27 @@ static int write_all (int fd, const mio_bch_t* ptr, mio_oow_t len)
 
 static int write_log (mio_t* mio, int fd, const mio_bch_t* ptr, mio_oow_t len)
 {
-	xtn_t* xtn = GET_XTN(mio);
+	mio_sys_log_t* log = mio->sys.log;
 
 	while (len > 0)
 	{
-		if (xtn->log.out.len > 0)
+		if (log->out.len > 0)
 		{
 			mio_oow_t rcapa, cplen;
 
-			rcapa = MIO_COUNTOF(xtn->log.out.buf) - xtn->log.out.len;
+			rcapa = MIO_COUNTOF(log->out.buf) - log->out.len;
 			cplen = (len >= rcapa)? rcapa: len;
 
-			MIO_MEMCPY (&xtn->log.out.buf[xtn->log.out.len], ptr, cplen);
-			xtn->log.out.len += cplen;
+			MIO_MEMCPY (&log->out.buf[log->out.len], ptr, cplen);
+			log->out.len += cplen;
 			ptr += cplen;
 			len -= cplen;
 
-			if (xtn->log.out.len >= MIO_COUNTOF(xtn->log.out.buf))
+			if (log->out.len >= MIO_COUNTOF(log->out.buf))
 			{
 				int n;
-				n = write_all(fd, xtn->log.out.buf, xtn->log.out.len);
-				xtn->log.out.len = 0;
+				n = write_all(fd, log->out.buf, log->out.len);
+				log->out.len = 0;
 				if (n <= -1) return -1;
 			}
 		}
@@ -168,7 +165,7 @@ static int write_log (mio_t* mio, int fd, const mio_bch_t* ptr, mio_oow_t len)
 		{
 			mio_oow_t rcapa;
 
-			rcapa = MIO_COUNTOF(xtn->log.out.buf);
+			rcapa = MIO_COUNTOF(log->out.buf);
 			if (len >= rcapa)
 			{
 				if (write_all(fd, ptr, rcapa) <= -1) return -1;
@@ -177,8 +174,8 @@ static int write_log (mio_t* mio, int fd, const mio_bch_t* ptr, mio_oow_t len)
 			}
 			else
 			{
-				MIO_MEMCPY (xtn->log.out.buf, ptr, len);
-				xtn->log.out.len += len;
+				MIO_MEMCPY (log->out.buf, ptr, len);
+				log->out.len += len;
 				ptr += len;
 				len -= len;
 				
@@ -191,37 +188,31 @@ static int write_log (mio_t* mio, int fd, const mio_bch_t* ptr, mio_oow_t len)
 
 static void flush_log (mio_t* mio, int fd)
 {
-	xtn_t* xtn = GET_XTN(mio);
-	if (xtn->log.out.len > 0)
+	mio_sys_log_t* log = mio->sys.log;
+	if (log->out.len > 0)
 	{
-		write_all (fd, xtn->log.out.buf, xtn->log.out.len);
-		xtn->log.out.len = 0;
+		write_all (fd, log->out.buf, log->out.len);
+		log->out.len = 0;
 	}
 }
 
 void mio_sys_writelog (mio_t* mio, mio_bitmask_t mask, const mio_ooch_t* msg, mio_oow_t len)
 {
-	xtn_t* xtn = GET_XTN(mio);
+	mio_sys_log_t* log = mio->sys.log;
 	mio_bch_t buf[256];
 	mio_oow_t ucslen, bcslen, msgidx;
 	int n, logfd;
 
 	if (mask & MIO_LOG_STDERR)
 	{
-		/* the messages that go to STDERR don't get masked out */
 		logfd = 2;
 	}
 	else
 	{
-#if 0
-		if (!(xtn->log.mask & mask & ~MIO_LOG_ALL_LEVELS)) return;  /* check log types */
-		if (!(xtn->log.mask & mask & ~MIO_LOG_ALL_TYPES)) return;  /* check log levels */
-#endif
-
 		if (mask & MIO_LOG_STDOUT) logfd = 1;
 		else
 		{
-			logfd = xtn->log.fd;
+			logfd = log->fd;
 			if (logfd <= -1) return;
 		}
 	}
@@ -285,7 +276,7 @@ void mio_sys_writelog (mio_t* mio, mio_bitmask_t mask, const mio_ooch_t* msg, mi
 		write_log (mio, logfd, ts, tslen);
 	}
 
-	if (logfd == xtn->log.fd && (xtn->log.fd_flag & LOGFD_TTY))
+	if (logfd == log->fd && (log->fd_flag & LOGFD_TTY))
 	{
 		if (mask & MIO_LOG_FATAL) write_log (mio, logfd, "\x1B[1;31m", 7);
 		else if (mask & MIO_LOG_ERROR) write_log (mio, logfd, "\x1B[1;32m", 7);
@@ -330,7 +321,7 @@ void mio_sys_writelog (mio_t* mio, mio_bitmask_t mask, const mio_ooch_t* msg, mi
 	write_log (mio, logfd, msg, len);
 #endif
 
-	if (logfd == xtn->log.fd && (xtn->log.fd_flag & LOGFD_TTY))
+	if (logfd == log->fd && (log->fd_flag & LOGFD_TTY))
 	{
 		if (mask & (MIO_LOG_FATAL | MIO_LOG_ERROR | MIO_LOG_WARN)) write_log (mio, logfd, "\x1B[0m", 4);
 	}
@@ -338,51 +329,51 @@ void mio_sys_writelog (mio_t* mio, mio_bitmask_t mask, const mio_ooch_t* msg, mi
 	flush_log (mio, logfd);
 }
 
-static MIO_INLINE void reset_log_to_default (xtn_t* xtn)
+int mio_sys_initlog (mio_t* mio)
 {
-#if defined(ENABLE_LOG_INITIALLY)
-	xtn->log.fd = 2;
-	xtn->log.fd_flag = 0;
-	#if defined(HAVE_ISATTY)
-	if (isatty(xtn->log.fd)) xtn->log.fd_flag |= LOGFD_TTY;
-	#endif
-#else
-	xtn->log.fd = -1;
-	xtn->log.fd_flag = 0;
-#endif
-}
-
-void mio_sys_initlog (mio_t* mio)
-{
-	xtn_t* xtn = GET_XTN(mio);
+	mio_sys_log_t* log;
 	mio_bitmask_t logmask;
-	mio_oow_t pathlen;
+	/*mio_oow_t pathlen;*/
+
+	log = (mio_sys_log_t*)mio_callocmem(mio, MIO_SIZEOF(*log));
+	if (!log) return -1;
 
 /* TODO: */
 #define LOG_FILE "/dev/stderr"
-	xtn->log.fd = open(LOG_FILE, O_CREAT | O_WRONLY | O_APPEND , 0644);
-	if (xtn->log.fd == -1)
+	log->fd = open(LOG_FILE, O_CREAT | O_WRONLY | O_APPEND , 0644);
+	if (log->fd == -1)
 	{
 		/*mio_seterrbfmtwithsyserr (mio, 0, errno, "cannot open log file %hs", LOG_FILE);*/
-		xtn->log.fd = 2;
-		xtn->log.fd_flag = 0;
+		log->fd = 2;
+		log->fd_flag = 0;
 	}
 	else
 	{
-		xtn->log.fd_flag |= LOGFD_OPENED_HERE;
+		log->fd_flag |= LOGFD_OPENED_HERE;
 	}
 
 #if defined(HAVE_ISATTY)
-	if (isatty(xtn->log.fd)) xtn->log.fd_flag |= LOGFD_TTY;
+	if (isatty(log->fd)) log->fd_flag |= LOGFD_TTY;
 #endif
 
 	logmask = MIO_LOG_ALL_TYPES | MIO_LOG_ALL_LEVELS;
 	mio_setoption (mio, MIO_LOG_MASK, &logmask);
+
+	mio->sys.log = log;
+	return 0;
 }
 
 void mio_sys_finilog (mio_t* mio)
 {
-	xtn_t* xtn = GET_XTN(mio);
-	if ((xtn->log.fd_flag & LOGFD_OPENED_HERE) && xtn->log.fd >= 0) close (xtn->log.fd);
-	reset_log_to_default (xtn);
+	mio_sys_log_t* log = mio->sys.log;
+
+	if ((log->fd_flag & LOGFD_OPENED_HERE) && log->fd >= 0) 
+	{
+		close (log->fd);
+		log->fd = -1;
+		log->fd_flag = 0;
+	}
+
+	mio_freemem (mio, log);
+	mio->sys.log = MIO_NULL;
 }
diff --git a/mio/lib/sys-mux.c b/mio/lib/sys-mux.c
index 97ddea4..6655ea6 100644
--- a/mio/lib/sys-mux.c
+++ b/mio/lib/sys-mux.c
@@ -86,11 +86,10 @@ void mio_sys_finimux (mio_t* mio)
 
 int mio_sys_ctrlmux (mio_t* mio, mio_sys_mux_cmd_t cmd, mio_dev_t* dev, int dev_capa)
 {
-	mio_t* mio;
+	mio_t* mio = dev->mio;
 	mio_sys_mux_t* mux;
 	mio_oow_t idx;
 
-	mio = dev->mio;
 	mux = (mio_sys_mux_t*)mio->sys.mux;
 
 	if (hnd >= mux->map.capa)
@@ -372,9 +371,10 @@ int mio_sys_waitmux (mio_t* mio, const mio_ntime_t* tmout, mio_sys_mux_evtcb_t e
 
 		event_handler (mio, dev, events, rdhup);
 	}
-
 #else
 
 #	error NO SUPPORTED MULTIPLEXER
 #endif
+
+	return 0;
 }
diff --git a/mio/lib/tmr.c b/mio/lib/tmr.c
index 33b9fe1..7b93537 100644
--- a/mio/lib/tmr.c
+++ b/mio/lib/tmr.c
@@ -139,12 +139,8 @@ mio_tmridx_t mio_instmrjob (mio_t* mio, const mio_tmrjob_t* job)
 
 		MIO_ASSERT (mio, mio->tmr.capa >= 1);
 		new_capa = mio->tmr.capa * 2;
-		tmp = (mio_tmrjob_t*)MIO_MMGR_REALLOC (mio->mmgr, mio->tmr.jobs, new_capa * MIO_SIZEOF(*tmp));
-		if (tmp == MIO_NULL) 
-		{
-			mio->errnum = MIO_ESYSMEM;
-			return MIO_TMRIDX_INVALID;
-		}
+		tmp = (mio_tmrjob_t*)mio_reallocmem(mio, mio->tmr.jobs, new_capa * MIO_SIZEOF(*tmp));
+		if (!tmp) return MIO_TMRIDX_INVALID;
 
 		mio->tmr.jobs = tmp;
 		mio->tmr.capa = new_capa;
@@ -153,7 +149,7 @@ mio_tmridx_t mio_instmrjob (mio_t* mio, const mio_tmrjob_t* job)
 	mio->tmr.size = mio->tmr.size + 1;
 	mio->tmr.jobs[index] = *job;
 	if (mio->tmr.jobs[index].idxptr) *mio->tmr.jobs[index].idxptr = index;
-	return sift_up (mio, index, 0);
+	return sift_up(mio, index, 0);
 }
 
 mio_tmridx_t mio_updtmrjob (mio_t* mio, mio_tmridx_t index, const mio_tmrjob_t* job)
@@ -196,7 +192,7 @@ int mio_gettmrtmout (mio_t* mio, const mio_ntime_t* tm, mio_ntime_t* tmout)
 	/* time-out can't be calculated when there's no job scheduled */
 	if (mio->tmr.size <= 0) 
 	{
-		mio->errnum = MIO_ENOENT;
+		mio_seterrbfmt (mio, MIO_ENOENT, "unable to compute timeout as no job is scheduled");
 		return -1;
 	}
 
@@ -214,7 +210,7 @@ mio_tmrjob_t* mio_gettmrjob (mio_t* mio, mio_tmridx_t index)
 {
 	if (index < 0 || index >= mio->tmr.size)
 	{
-		mio->errnum = MIO_ENOENT;
+		mio_seterrbfmt (mio, MIO_ENOENT, "unable to get timer job as the given index is out of range");
 		return MIO_NULL;
 	}
 
@@ -225,7 +221,7 @@ int mio_gettmrjobdeadline (mio_t* mio, mio_tmridx_t index, mio_ntime_t* deadline
 {
 	if (index < 0 || index >= mio->tmr.size)
 	{
-		mio->errnum = MIO_ENOENT;
+		mio_seterrbfmt (mio, MIO_ENOENT, "unable to get timer job deadline as the given index is out of range");
 		return -1;
 	}
 
diff --git a/mio/lib/utl.c b/mio/lib/utl.c
index 03b727a..3a4bb31 100644
--- a/mio/lib/utl.c
+++ b/mio/lib/utl.c
@@ -39,12 +39,8 @@ mio_bch_t* mio_mbsdup (mio_t* mio, const mio_bch_t* src)
 	while (*dst != MIO_MT('\0')) dst++;
 	len = dst - src;
 
-	dst = MIO_MMGR_ALLOC (mio->mmgr, (len + 1) * MIO_SIZEOF(*src));
-	if (!dst)
-	{
-		mio->errnum = MIO_ESYSMEM;
-		return MIO_NULL;
-	}
+	dst = mio_allocmem(mio, (len + 1) * MIO_SIZEOF(*src));
+	if (!dst) return MIO_NULL;
 
 	MIO_MEMCPY (dst, src, (len + 1) * MIO_SIZEOF(*src));
 	return dst;