diff --git a/qse/include/qse/si/Condition.hpp b/qse/include/qse/si/Condition.hpp
new file mode 100644
index 00000000..b0c9ee33
--- /dev/null
+++ b/qse/include/qse/si/Condition.hpp
@@ -0,0 +1,68 @@
+/*
+ * $Id$
+ *
+    Copyright (c) 2006-2014 Chung, Hyung-Hwan. All rights reserved.
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions
+    are met:
+    1. Redistributions of source code must retain the above copyright
+       notice, this list of conditions and the following disclaimer.
+    2. Redistributions in binary form must reproduce the above copyright
+       notice, this list of conditions and the following disclaimer in the
+       documentation and/or other materials provided with the distribution.
+
+    THIS SOFTWARE IS PROVIDED BY THE AUTHOR "AS IS" AND ANY EQSERESS OR
+    IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+    OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+    IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+    NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+    THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _QSE_SI_CONDITION_CLASS_
+#define _QSE_SI_CONDITION_CLASS_
+
+#include <qse/si/cnd.h>
+#include <qse/si/Mutex.hpp>
+
+QSE_BEGIN_NAMESPACE(QSE)
+
+class Condition: public Uncopyable
+{
+public:
+	Condition() QSE_CPP_NOEXCEPT 
+	{
+		qse_cnd_init (&this->cnd, QSE_NULL);
+	}
+	~Condition() QSE_CPP_NOEXCEPT
+	{
+		qse_cnd_fini (&this->cnd);
+	}
+
+	void signal ()
+	{
+		qse_cnd_signal (&this->cnd);
+	}
+
+	void broadcast ()
+	{
+		qse_cnd_broadcast (&this->cnd);
+	}
+
+	void wait (Mutex& mtx, const qse_ntime_t* timeout = QSE_NULL)
+	{
+		qse_cnd_wait (&this->cnd, &mtx.mtx, timeout);
+	}
+
+protected:
+	qse_cnd_t cnd;
+};
+
+QSE_END_NAMESPACE(QSE)
+
+#endif
diff --git a/qse/include/qse/si/Makefile.am b/qse/include/qse/si/Makefile.am
index 4e80e040..448d742c 100644
--- a/qse/include/qse/si/Makefile.am
+++ b/qse/include/qse/si/Makefile.am
@@ -30,6 +30,7 @@ pkginclude_HEADERS = \
 if ENABLE_CXX
 pkginclude_HEADERS += \
 	AppRoot.hpp \
+	Condition.hpp \
 	Mutex.hpp \
 	SocketAddress.hpp \
 	Socket.hpp \
diff --git a/qse/include/qse/si/Makefile.in b/qse/include/qse/si/Makefile.in
index e8f9b4b5..933240c4 100644
--- a/qse/include/qse/si/Makefile.in
+++ b/qse/include/qse/si/Makefile.in
@@ -89,6 +89,7 @@ build_triplet = @build@
 host_triplet = @host@
 @ENABLE_CXX_TRUE@am__append_1 = \
 @ENABLE_CXX_TRUE@	AppRoot.hpp \
+@ENABLE_CXX_TRUE@	Condition.hpp \
 @ENABLE_CXX_TRUE@	Mutex.hpp \
 @ENABLE_CXX_TRUE@	SocketAddress.hpp \
 @ENABLE_CXX_TRUE@	Socket.hpp \
@@ -135,8 +136,8 @@ am__can_run_installinfo = \
 am__pkginclude_HEADERS_DIST = aio.h aio-pro.h aio-sck.h cnd.h dir.h \
 	fio.h fs.h glob.h intr.h log.h mtx.h mux.h nwad.h nwif.h \
 	nwio.h os.h pio.h rwl.h sck.h sinfo.h sio.h spl.h task.h thr.h \
-	tio.h AppRoot.hpp Mutex.hpp SocketAddress.hpp Socket.hpp \
-	SpinLock.hpp TcpServer.hpp Thread.hpp
+	tio.h AppRoot.hpp Condition.hpp Mutex.hpp SocketAddress.hpp \
+	Socket.hpp SpinLock.hpp TcpServer.hpp Thread.hpp
 am__vpath_adj_setup = srcdirstrip=`echo "$(srcdir)" | sed 's|.|.|g'`;
 am__vpath_adj = case $$p in \
     $(srcdir)/*) f=`echo "$$p" | sed "s|^$$srcdirstrip/||"`;; \
diff --git a/qse/include/qse/si/Mutex.hpp b/qse/include/qse/si/Mutex.hpp
index 1e37ce65..0c87affc 100644
--- a/qse/include/qse/si/Mutex.hpp
+++ b/qse/include/qse/si/Mutex.hpp
@@ -36,6 +36,8 @@ QSE_BEGIN_NAMESPACE(QSE)
 class Mutex: public Uncopyable
 {
 public:
+	friend class Condition;
+
 	Mutex() QSE_CPP_NOEXCEPT 
 	{
 		qse_mtx_init (&this->mtx, QSE_NULL);
diff --git a/qse/include/qse/si/cnd.h b/qse/include/qse/si/cnd.h
index 25692317..fe032054 100644
--- a/qse/include/qse/si/cnd.h
+++ b/qse/include/qse/si/cnd.h
@@ -134,6 +134,11 @@ QSE_EXPORT void qse_cnd_broadcast (
 	qse_cnd_t* cond
 );
 
+/**
+ * The qse_cnd_wait() function blocks the calling thread until the condition
+ * variable is signaled. The caller must lock the mutex before calling this
+ * function and unlock the mutex after this function finishes.
+ */
 QSE_EXPORT void qse_cnd_wait (
 	qse_cnd_t*         cond, 
 	qse_mtx_t*         mutex,
diff --git a/qse/samples/si/Makefile.am b/qse/samples/si/Makefile.am
index 8b10d3fa..ffcc6458 100644
--- a/qse/samples/si/Makefile.am
+++ b/qse/samples/si/Makefile.am
@@ -65,17 +65,19 @@ if ENABLE_CXX
 
 CXXLIB = -lqsesixx -lqsecmnxx
 
-bin_PROGRAMS += sck01 spl02 tcpsvr01 thr02
+bin_PROGRAMS += sck01 spl02 tcpsvr01 thr02 thr03
 
 sck01_SOURCES = sck01.cpp
 spl02_SOURCES = spl02.cpp
 tcpsvr01_SOURCES = tcpsvr01.cpp
 thr02_SOURCES = thr02.cpp
+thr03_SOURCES = thr03.cpp
 
 sck01_LDADD = $(CXXLIB) $(LDADD)
 spl02_LDADD = $(CXXLIB) $(LDADD)
 tcpsvr01_LDADD = $(CXXLIB) $(LDADD)
 thr02_LDADD = $(CXXLIB) $(LDADD)
+thr03_LDADD = $(CXXLIB) $(LDADD)
 
 endif
 
diff --git a/qse/samples/si/Makefile.in b/qse/samples/si/Makefile.in
index 1ee5ac3a..f57a8e00 100644
--- a/qse/samples/si/Makefile.in
+++ b/qse/samples/si/Makefile.in
@@ -95,7 +95,7 @@ bin_PROGRAMS = aio01$(EXEEXT) dir01$(EXEEXT) fio01$(EXEEXT) \
 	sio01$(EXEEXT) sio02$(EXEEXT) sio03$(EXEEXT) spl01$(EXEEXT) \
 	task01$(EXEEXT) thr01$(EXEEXT) $(am__EXEEXT_1)
 @WCHAR_TRUE@@WIN32_TRUE@am__append_1 = $(UNICOWS_LIBS)
-@ENABLE_CXX_TRUE@am__append_2 = sck01 spl02 tcpsvr01 thr02
+@ENABLE_CXX_TRUE@am__append_2 = sck01 spl02 tcpsvr01 thr02 thr03
 subdir = samples/si
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/ax_check_sign.m4 \
@@ -113,7 +113,8 @@ CONFIG_HEADER = $(top_builddir)/include/qse/config.h
 CONFIG_CLEAN_FILES =
 CONFIG_CLEAN_VPATH_FILES =
 @ENABLE_CXX_TRUE@am__EXEEXT_1 = sck01$(EXEEXT) spl02$(EXEEXT) \
-@ENABLE_CXX_TRUE@	tcpsvr01$(EXEEXT) thr02$(EXEEXT)
+@ENABLE_CXX_TRUE@	tcpsvr01$(EXEEXT) thr02$(EXEEXT) \
+@ENABLE_CXX_TRUE@	thr03$(EXEEXT)
 am__installdirs = "$(DESTDIR)$(bindir)"
 PROGRAMS = $(bin_PROGRAMS)
 am_aio01_OBJECTS = aio01.$(OBJEXT)
@@ -223,6 +224,11 @@ am__thr02_SOURCES_DIST = thr02.cpp
 thr02_OBJECTS = $(am_thr02_OBJECTS)
 @ENABLE_CXX_TRUE@thr02_DEPENDENCIES = $(am__DEPENDENCIES_1) \
 @ENABLE_CXX_TRUE@	$(am__DEPENDENCIES_3)
+am__thr03_SOURCES_DIST = thr03.cpp
+@ENABLE_CXX_TRUE@am_thr03_OBJECTS = thr03.$(OBJEXT)
+thr03_OBJECTS = $(am_thr03_OBJECTS)
+@ENABLE_CXX_TRUE@thr03_DEPENDENCIES = $(am__DEPENDENCIES_1) \
+@ENABLE_CXX_TRUE@	$(am__DEPENDENCIES_3)
 AM_V_P = $(am__v_P_@AM_V@)
 am__v_P_ = $(am__v_P_@AM_DEFAULT_V@)
 am__v_P_0 = false
@@ -282,7 +288,8 @@ SOURCES = $(aio01_SOURCES) $(dir01_SOURCES) $(fio01_SOURCES) \
 	$(pio01_SOURCES) $(rwl01_SOURCES) $(sck01_SOURCES) \
 	$(sio01_SOURCES) $(sio02_SOURCES) $(sio03_SOURCES) \
 	$(spl01_SOURCES) $(spl02_SOURCES) $(task01_SOURCES) \
-	$(tcpsvr01_SOURCES) $(thr01_SOURCES) $(thr02_SOURCES)
+	$(tcpsvr01_SOURCES) $(thr01_SOURCES) $(thr02_SOURCES) \
+	$(thr03_SOURCES)
 DIST_SOURCES = $(aio01_SOURCES) $(dir01_SOURCES) $(fio01_SOURCES) \
 	$(fio02_SOURCES) $(fs01_SOURCES) $(fs02_SOURCES) \
 	$(fs03_SOURCES) $(glob01_SOURCES) $(log01_SOURCES) \
@@ -291,7 +298,7 @@ DIST_SOURCES = $(aio01_SOURCES) $(dir01_SOURCES) $(fio01_SOURCES) \
 	$(sio01_SOURCES) $(sio02_SOURCES) $(sio03_SOURCES) \
 	$(spl01_SOURCES) $(am__spl02_SOURCES_DIST) $(task01_SOURCES) \
 	$(am__tcpsvr01_SOURCES_DIST) $(thr01_SOURCES) \
-	$(am__thr02_SOURCES_DIST)
+	$(am__thr02_SOURCES_DIST) $(am__thr03_SOURCES_DIST)
 am__can_run_installinfo = \
   case $$AM_UPDATE_INFO_DIR in \
     n|no|NO) false;; \
@@ -517,10 +524,12 @@ thr01_SOURCES = thr01.c
 @ENABLE_CXX_TRUE@spl02_SOURCES = spl02.cpp
 @ENABLE_CXX_TRUE@tcpsvr01_SOURCES = tcpsvr01.cpp
 @ENABLE_CXX_TRUE@thr02_SOURCES = thr02.cpp
+@ENABLE_CXX_TRUE@thr03_SOURCES = thr03.cpp
 @ENABLE_CXX_TRUE@sck01_LDADD = $(CXXLIB) $(LDADD)
 @ENABLE_CXX_TRUE@spl02_LDADD = $(CXXLIB) $(LDADD)
 @ENABLE_CXX_TRUE@tcpsvr01_LDADD = $(CXXLIB) $(LDADD)
 @ENABLE_CXX_TRUE@thr02_LDADD = $(CXXLIB) $(LDADD)
+@ENABLE_CXX_TRUE@thr03_LDADD = $(CXXLIB) $(LDADD)
 all: all-am
 
 .SUFFIXES:
@@ -700,6 +709,10 @@ thr02$(EXEEXT): $(thr02_OBJECTS) $(thr02_DEPENDENCIES) $(EXTRA_thr02_DEPENDENCIE
 	@rm -f thr02$(EXEEXT)
 	$(AM_V_CXXLD)$(CXXLINK) $(thr02_OBJECTS) $(thr02_LDADD) $(LIBS)
 
+thr03$(EXEEXT): $(thr03_OBJECTS) $(thr03_DEPENDENCIES) $(EXTRA_thr03_DEPENDENCIES) 
+	@rm -f thr03$(EXEEXT)
+	$(AM_V_CXXLD)$(CXXLINK) $(thr03_OBJECTS) $(thr03_LDADD) $(LIBS)
+
 mostlyclean-compile:
 	-rm -f *.$(OBJEXT)
 
@@ -730,6 +743,7 @@ distclean-compile:
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/tcpsvr01.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/thr01.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/thr02.Po@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/thr03.Po@am__quote@
 
 .c.o:
 @am__fastdepCC_TRUE@	$(AM_V_CC)$(COMPILE) -MT $@ -MD -MP -MF $(DEPDIR)/$*.Tpo -c -o $@ $<
diff --git a/qse/samples/si/thr03.cpp b/qse/samples/si/thr03.cpp
new file mode 100644
index 00000000..3b095dfe
--- /dev/null
+++ b/qse/samples/si/thr03.cpp
@@ -0,0 +1,186 @@
+#include <qse/si/Thread.hpp>
+#include <qse/si/Condition.hpp>
+#include <qse/si/mtx.h>
+#include <qse/si/sio.h>
+#include <qse/cmn/mem.h>
+#include <qse/cmn/HeapMmgr.hpp>
+
+
+#include <locale.h>
+#if defined(_WIN32)
+#	include <windows.h>
+#endif
+
+#include <unistd.h>
+#include <signal.h>
+#include <string.h>
+
+static int g_stopreq = 0;
+static qse_mtx_t* g_prmtx = QSE_NULL;
+
+QSE::HeapMmgr g_heap_mmgr (QSE::Mmgr::getDFL(), 30000);
+
+struct rq_data_t
+{
+	rq_data_t(): stop(0) {}
+	int stop;
+	QSE::Mutex mtx;
+	QSE::Condition cnd;
+};
+
+class Waiter
+{
+public:
+	int operator() (QSE::Thread* thr)
+	{
+		int i = 0;
+		rq_data_t* rqdata = (rq_data_t*)thr->getContext();
+
+		while (1)
+		{
+			rqdata->mtx.lock ();
+			if (rqdata->stop)
+			{
+				rqdata->mtx.unlock ();
+				break;
+			}
+			rqdata->cnd.wait(rqdata->mtx);
+			rqdata->mtx.unlock ();
+
+			qse_mtx_lock (g_prmtx, QSE_NULL);
+			qse_printf (QSE_T("[%p] -> loop %d\n"), this, i);
+			qse_mtx_unlock (g_prmtx);
+			i++;
+		}
+
+		qse_mtx_lock (g_prmtx, QSE_NULL);
+		qse_printf (QSE_T("[%p] -> exiting\n"), this);
+		qse_mtx_unlock (g_prmtx);
+		return i;
+	}
+};
+
+static int test1 (void)
+{
+	g_prmtx = qse_mtx_open (QSE_MMGR_GETDFL(), 0);
+
+	rq_data_t rqdata;
+	QSE::ThreadF<Waiter> thr[3];
+
+	for (int i = 0; i < 3; i++)
+	{
+		thr[i].setStackSize (64000);
+		thr[i].setContext (&rqdata);
+		if (thr[i].start(QSE::Thread::SIGNALS_BLOCKED) <= -1)
+		{
+			qse_printf (QSE_T("cannot start thread%d\n"), i);
+			return -1;
+		}
+	}
+
+	while (1)
+	{
+		if (g_stopreq) 
+		{
+			qse_mtx_lock (g_prmtx, QSE_NULL);
+			qse_printf (QSE_T("broadcasting stop ---> 1\n"));
+			qse_mtx_unlock (g_prmtx);
+
+			rqdata.mtx.lock ();
+			rqdata.stop = 1;
+			rqdata.mtx.unlock ();
+			rqdata.cnd.broadcast ();
+		}
+
+		int nterm = 0;
+		for (int i = 0; i < 3; i++)
+		{
+			if (thr[i].getState() == QSE::Thread::TERMINATED) nterm++;
+		}
+		if (nterm == 3) break;
+
+		qse_mtx_lock (g_prmtx, QSE_NULL);
+		qse_printf (QSE_T("signalling ....(nterm = %d)\n"), nterm);
+		qse_mtx_unlock (g_prmtx);
+
+		rqdata.cnd.signal ();
+		sleep (1);
+	}
+
+
+	for (int i = 0; i < 3; i++)
+	{
+		thr[i].join();
+	}
+
+	for (int i = 0; i < 3; i++)
+	{
+		qse_printf (QSE_T("thread%d ended with retcode %d\n"), i, thr[i].getReturnCode());
+	}
+
+	qse_mtx_close (g_prmtx);
+	return 0;
+}
+
+
+static void handle_sigint (int sig, siginfo_t* siginfo, void* ctx)
+{
+	g_stopreq = 1;
+}
+
+static void set_signal (int sig, void(*handler)(int, siginfo_t*, void*))
+{
+	struct sigaction sa;
+ 
+	memset (&sa, 0, sizeof(sa));
+	/*sa.sa_handler = handler;*/
+	sa.sa_flags = SA_SIGINFO;
+	sa.sa_sigaction = handler;
+	sigemptyset (&sa.sa_mask);
+ 
+	sigaction (sig, &sa, NULL);
+}
+ 
+static void set_signal_to_default (int sig)
+{
+	struct sigaction sa;
+ 
+	memset (&sa, 0, sizeof(sa));
+	sa.sa_handler = SIG_DFL;
+	sa.sa_flags = 0;
+	sigemptyset (&sa.sa_mask);
+ 
+	sigaction (sig, &sa, NULL);
+}
+ 
+int main ()
+{
+#if defined(_WIN32)
+ 	char locale[100];
+	UINT codepage = GetConsoleOutputCP();
+	if (codepage == CP_UTF8)
+	{
+		/*SetConsoleOUtputCP (CP_UTF8);*/
+		qse_setdflcmgrbyid (QSE_CMGR_UTF8);
+	}
+	else
+	{
+		sprintf (locale, ".%u", (unsigned int)codepage);
+		setlocale (LC_ALL, locale);
+		/*qse_setdflcmgrbyid (QSE_CMGR_SLMB);*/
+	}
+#else
+	setlocale (LC_ALL, "");
+	/*qse_setdflcmgrbyid (QSE_CMGR_SLMB);*/
+#endif
+
+	set_signal (SIGINT, handle_sigint);
+
+	qse_open_stdsios ();
+	test1();
+	qse_close_stdsios ();
+
+	set_signal_to_default (SIGINT);
+
+	return 0;
+}