Index: src/examples/multicore.c
===================================================================
--- src/examples/multicore.c	(revision ca1a5475f4eddc0c66780db2fd4589594588899b)
+++ src/examples/multicore.c	(revision 24cde55896b292c3bb610ade3c9b9286c0c7a9f9)
@@ -19,8 +19,5 @@
 		processor p;
 		{
-			scoped(MyThread) f1;
-			scoped(MyThread) f2;
-			scoped(MyThread) f3;
-			scoped(MyThread) f4;
+			scoped(MyThread) f[4];
 		}
 	}
Index: src/libcfa/Makefile.am
===================================================================
--- src/libcfa/Makefile.am	(revision ca1a5475f4eddc0c66780db2fd4589594588899b)
+++ src/libcfa/Makefile.am	(revision 24cde55896b292c3bb610ade3c9b9286c0c7a9f9)
@@ -44,5 +44,5 @@
 # not all platforms support concurrency, add option do disable it
 if BUILD_CONCURRENCY
-headers += containers/vector concurrency/coroutines concurrency/threads concurrency/kernel
+headers += containers/vector concurrency/coroutines concurrency/threads concurrency/kernel concurrency/monitor
 endif
 
Index: src/libcfa/Makefile.in
===================================================================
--- src/libcfa/Makefile.in	(revision ca1a5475f4eddc0c66780db2fd4589594588899b)
+++ src/libcfa/Makefile.in	(revision 24cde55896b292c3bb610ade3c9b9286c0c7a9f9)
@@ -43,5 +43,5 @@
 
 # not all platforms support concurrency, add option do disable it
-@BUILD_CONCURRENCY_TRUE@am__append_3 = containers/vector concurrency/coroutines concurrency/threads concurrency/kernel
+@BUILD_CONCURRENCY_TRUE@am__append_3 = containers/vector concurrency/coroutines concurrency/threads concurrency/kernel concurrency/monitor
 
 # not all platforms support concurrency, add option do disable it
@@ -101,10 +101,12 @@
 	containers/vector.c concurrency/coroutines.c \
 	concurrency/threads.c concurrency/kernel.c \
-	concurrency/CtxSwitch-@MACHINE_TYPE@.S concurrency/invoke.c
+	concurrency/monitor.c concurrency/CtxSwitch-@MACHINE_TYPE@.S \
+	concurrency/invoke.c
 am__dirstamp = $(am__leading_dot)dirstamp
 @BUILD_CONCURRENCY_TRUE@am__objects_1 = containers/libcfa_d_a-vector.$(OBJEXT) \
 @BUILD_CONCURRENCY_TRUE@	concurrency/libcfa_d_a-coroutines.$(OBJEXT) \
 @BUILD_CONCURRENCY_TRUE@	concurrency/libcfa_d_a-threads.$(OBJEXT) \
-@BUILD_CONCURRENCY_TRUE@	concurrency/libcfa_d_a-kernel.$(OBJEXT)
+@BUILD_CONCURRENCY_TRUE@	concurrency/libcfa_d_a-kernel.$(OBJEXT) \
+@BUILD_CONCURRENCY_TRUE@	concurrency/libcfa_d_a-monitor.$(OBJEXT)
 am__objects_2 = libcfa_d_a-limits.$(OBJEXT) \
 	libcfa_d_a-stdlib.$(OBJEXT) libcfa_d_a-math.$(OBJEXT) \
@@ -124,10 +126,12 @@
 	containers/vector.c concurrency/coroutines.c \
 	concurrency/threads.c concurrency/kernel.c \
-	concurrency/CtxSwitch-@MACHINE_TYPE@.S concurrency/invoke.c
+	concurrency/monitor.c concurrency/CtxSwitch-@MACHINE_TYPE@.S \
+	concurrency/invoke.c
 @BUILD_CONCURRENCY_TRUE@am__objects_5 =  \
 @BUILD_CONCURRENCY_TRUE@	containers/libcfa_a-vector.$(OBJEXT) \
 @BUILD_CONCURRENCY_TRUE@	concurrency/libcfa_a-coroutines.$(OBJEXT) \
 @BUILD_CONCURRENCY_TRUE@	concurrency/libcfa_a-threads.$(OBJEXT) \
-@BUILD_CONCURRENCY_TRUE@	concurrency/libcfa_a-kernel.$(OBJEXT)
+@BUILD_CONCURRENCY_TRUE@	concurrency/libcfa_a-kernel.$(OBJEXT) \
+@BUILD_CONCURRENCY_TRUE@	concurrency/libcfa_a-monitor.$(OBJEXT)
 am__objects_6 = libcfa_a-limits.$(OBJEXT) libcfa_a-stdlib.$(OBJEXT) \
 	libcfa_a-math.$(OBJEXT) libcfa_a-iostream.$(OBJEXT) \
@@ -172,5 +176,6 @@
 	fstream iterator rational assert containers/vector \
 	concurrency/coroutines concurrency/threads concurrency/kernel \
-	${shell echo stdhdr/*} concurrency/invoke.h
+	concurrency/monitor ${shell echo stdhdr/*} \
+	concurrency/invoke.h
 HEADERS = $(nobase_cfa_include_HEADERS)
 ETAGS = etags
@@ -398,4 +403,6 @@
 concurrency/libcfa_d_a-kernel.$(OBJEXT): concurrency/$(am__dirstamp) \
 	concurrency/$(DEPDIR)/$(am__dirstamp)
+concurrency/libcfa_d_a-monitor.$(OBJEXT): concurrency/$(am__dirstamp) \
+	concurrency/$(DEPDIR)/$(am__dirstamp)
 concurrency/CtxSwitch-@MACHINE_TYPE@.$(OBJEXT):  \
 	concurrency/$(am__dirstamp) \
@@ -416,4 +423,6 @@
 concurrency/libcfa_a-kernel.$(OBJEXT): concurrency/$(am__dirstamp) \
 	concurrency/$(DEPDIR)/$(am__dirstamp)
+concurrency/libcfa_a-monitor.$(OBJEXT): concurrency/$(am__dirstamp) \
+	concurrency/$(DEPDIR)/$(am__dirstamp)
 concurrency/libcfa_a-invoke.$(OBJEXT): concurrency/$(am__dirstamp) \
 	concurrency/$(DEPDIR)/$(am__dirstamp)
@@ -429,8 +438,10 @@
 	-rm -f concurrency/libcfa_a-invoke.$(OBJEXT)
 	-rm -f concurrency/libcfa_a-kernel.$(OBJEXT)
+	-rm -f concurrency/libcfa_a-monitor.$(OBJEXT)
 	-rm -f concurrency/libcfa_a-threads.$(OBJEXT)
 	-rm -f concurrency/libcfa_d_a-coroutines.$(OBJEXT)
 	-rm -f concurrency/libcfa_d_a-invoke.$(OBJEXT)
 	-rm -f concurrency/libcfa_d_a-kernel.$(OBJEXT)
+	-rm -f concurrency/libcfa_d_a-monitor.$(OBJEXT)
 	-rm -f concurrency/libcfa_d_a-threads.$(OBJEXT)
 	-rm -f containers/libcfa_a-vector.$(OBJEXT)
@@ -462,8 +473,10 @@
 @AMDEP_TRUE@@am__include@ @am__quote@concurrency/$(DEPDIR)/libcfa_a-invoke.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@concurrency/$(DEPDIR)/libcfa_a-kernel.Po@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@concurrency/$(DEPDIR)/libcfa_a-monitor.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@concurrency/$(DEPDIR)/libcfa_a-threads.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@concurrency/$(DEPDIR)/libcfa_d_a-coroutines.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@concurrency/$(DEPDIR)/libcfa_d_a-invoke.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@concurrency/$(DEPDIR)/libcfa_d_a-kernel.Po@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@concurrency/$(DEPDIR)/libcfa_d_a-monitor.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@concurrency/$(DEPDIR)/libcfa_d_a-threads.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@containers/$(DEPDIR)/libcfa_a-vector.Po@am__quote@
@@ -677,4 +690,18 @@
 @am__fastdepCC_FALSE@	$(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(libcfa_d_a_CFLAGS) $(CFLAGS) -c -o concurrency/libcfa_d_a-kernel.obj `if test -f 'concurrency/kernel.c'; then $(CYGPATH_W) 'concurrency/kernel.c'; else $(CYGPATH_W) '$(srcdir)/concurrency/kernel.c'; fi`
 
+concurrency/libcfa_d_a-monitor.o: concurrency/monitor.c
+@am__fastdepCC_TRUE@	$(AM_V_CC)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(libcfa_d_a_CFLAGS) $(CFLAGS) -MT concurrency/libcfa_d_a-monitor.o -MD -MP -MF concurrency/$(DEPDIR)/libcfa_d_a-monitor.Tpo -c -o concurrency/libcfa_d_a-monitor.o `test -f 'concurrency/monitor.c' || echo '$(srcdir)/'`concurrency/monitor.c
+@am__fastdepCC_TRUE@	$(AM_V_at)$(am__mv) concurrency/$(DEPDIR)/libcfa_d_a-monitor.Tpo concurrency/$(DEPDIR)/libcfa_d_a-monitor.Po
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	$(AM_V_CC)source='concurrency/monitor.c' object='concurrency/libcfa_d_a-monitor.o' libtool=no @AMDEPBACKSLASH@
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
+@am__fastdepCC_FALSE@	$(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(libcfa_d_a_CFLAGS) $(CFLAGS) -c -o concurrency/libcfa_d_a-monitor.o `test -f 'concurrency/monitor.c' || echo '$(srcdir)/'`concurrency/monitor.c
+
+concurrency/libcfa_d_a-monitor.obj: concurrency/monitor.c
+@am__fastdepCC_TRUE@	$(AM_V_CC)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(libcfa_d_a_CFLAGS) $(CFLAGS) -MT concurrency/libcfa_d_a-monitor.obj -MD -MP -MF concurrency/$(DEPDIR)/libcfa_d_a-monitor.Tpo -c -o concurrency/libcfa_d_a-monitor.obj `if test -f 'concurrency/monitor.c'; then $(CYGPATH_W) 'concurrency/monitor.c'; else $(CYGPATH_W) '$(srcdir)/concurrency/monitor.c'; fi`
+@am__fastdepCC_TRUE@	$(AM_V_at)$(am__mv) concurrency/$(DEPDIR)/libcfa_d_a-monitor.Tpo concurrency/$(DEPDIR)/libcfa_d_a-monitor.Po
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	$(AM_V_CC)source='concurrency/monitor.c' object='concurrency/libcfa_d_a-monitor.obj' libtool=no @AMDEPBACKSLASH@
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
+@am__fastdepCC_FALSE@	$(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(libcfa_d_a_CFLAGS) $(CFLAGS) -c -o concurrency/libcfa_d_a-monitor.obj `if test -f 'concurrency/monitor.c'; then $(CYGPATH_W) 'concurrency/monitor.c'; else $(CYGPATH_W) '$(srcdir)/concurrency/monitor.c'; fi`
+
 concurrency/libcfa_d_a-invoke.obj: concurrency/invoke.c
 @am__fastdepCC_TRUE@	$(AM_V_CC)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(libcfa_d_a_CFLAGS) $(CFLAGS) -MT concurrency/libcfa_d_a-invoke.obj -MD -MP -MF concurrency/$(DEPDIR)/libcfa_d_a-invoke.Tpo -c -o concurrency/libcfa_d_a-invoke.obj `if test -f 'concurrency/invoke.c'; then $(CYGPATH_W) 'concurrency/invoke.c'; else $(CYGPATH_W) '$(srcdir)/concurrency/invoke.c'; fi`
@@ -858,4 +885,18 @@
 @AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
 @am__fastdepCC_FALSE@	$(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(libcfa_a_CFLAGS) $(CFLAGS) -c -o concurrency/libcfa_a-kernel.obj `if test -f 'concurrency/kernel.c'; then $(CYGPATH_W) 'concurrency/kernel.c'; else $(CYGPATH_W) '$(srcdir)/concurrency/kernel.c'; fi`
+
+concurrency/libcfa_a-monitor.o: concurrency/monitor.c
+@am__fastdepCC_TRUE@	$(AM_V_CC)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(libcfa_a_CFLAGS) $(CFLAGS) -MT concurrency/libcfa_a-monitor.o -MD -MP -MF concurrency/$(DEPDIR)/libcfa_a-monitor.Tpo -c -o concurrency/libcfa_a-monitor.o `test -f 'concurrency/monitor.c' || echo '$(srcdir)/'`concurrency/monitor.c
+@am__fastdepCC_TRUE@	$(AM_V_at)$(am__mv) concurrency/$(DEPDIR)/libcfa_a-monitor.Tpo concurrency/$(DEPDIR)/libcfa_a-monitor.Po
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	$(AM_V_CC)source='concurrency/monitor.c' object='concurrency/libcfa_a-monitor.o' libtool=no @AMDEPBACKSLASH@
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
+@am__fastdepCC_FALSE@	$(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(libcfa_a_CFLAGS) $(CFLAGS) -c -o concurrency/libcfa_a-monitor.o `test -f 'concurrency/monitor.c' || echo '$(srcdir)/'`concurrency/monitor.c
+
+concurrency/libcfa_a-monitor.obj: concurrency/monitor.c
+@am__fastdepCC_TRUE@	$(AM_V_CC)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(libcfa_a_CFLAGS) $(CFLAGS) -MT concurrency/libcfa_a-monitor.obj -MD -MP -MF concurrency/$(DEPDIR)/libcfa_a-monitor.Tpo -c -o concurrency/libcfa_a-monitor.obj `if test -f 'concurrency/monitor.c'; then $(CYGPATH_W) 'concurrency/monitor.c'; else $(CYGPATH_W) '$(srcdir)/concurrency/monitor.c'; fi`
+@am__fastdepCC_TRUE@	$(AM_V_at)$(am__mv) concurrency/$(DEPDIR)/libcfa_a-monitor.Tpo concurrency/$(DEPDIR)/libcfa_a-monitor.Po
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	$(AM_V_CC)source='concurrency/monitor.c' object='concurrency/libcfa_a-monitor.obj' libtool=no @AMDEPBACKSLASH@
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
+@am__fastdepCC_FALSE@	$(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(libcfa_a_CFLAGS) $(CFLAGS) -c -o concurrency/libcfa_a-monitor.obj `if test -f 'concurrency/monitor.c'; then $(CYGPATH_W) 'concurrency/monitor.c'; else $(CYGPATH_W) '$(srcdir)/concurrency/monitor.c'; fi`
 
 concurrency/libcfa_a-invoke.obj: concurrency/invoke.c
Index: src/libcfa/concurrency/kernel.c
===================================================================
--- src/libcfa/concurrency/kernel.c	(revision ca1a5475f4eddc0c66780db2fd4589594588899b)
+++ src/libcfa/concurrency/kernel.c	(revision 24cde55896b292c3bb610ade3c9b9286c0c7a9f9)
@@ -456,5 +456,5 @@
 
 void append( simple_thread_list * this, thread * t ) {
-	assert( t->next == NULL );
+	assert(this->tail != NULL);
 	*this->tail = t;
 	this->tail = &t->next;
@@ -470,5 +470,4 @@
 		head->next = NULL;
 	}	
-	
 	return head;
 }
Index: src/libcfa/concurrency/monitor
===================================================================
--- src/libcfa/concurrency/monitor	(revision 24cde55896b292c3bb610ade3c9b9286c0c7a9f9)
+++ src/libcfa/concurrency/monitor	(revision 24cde55896b292c3bb610ade3c9b9286c0c7a9f9)
@@ -0,0 +1,32 @@
+//                              -*- Mode: CFA -*-
+//
+// Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo
+//
+// The contents of this file are covered under the licence agreement in the
+// file "LICENCE" distributed with Cforall.
+//
+// monitor --
+//
+// Author           : Thierry Delisle
+// Created On       : Thd Feb 23 12:27:26 2017
+// Last Modified By : Thierry Delisle
+// Last Modified On : --
+// Update Count     : 0
+//
+
+#ifndef MONITOR_H
+#define MONITOR_H
+
+#include "assert"
+#include "invoke.h"
+
+struct monitor {
+	spinlock lock;
+	thread * holder;
+	simple_thread_list entry_queue;
+};
+
+void enter(monitor *);
+void leave(monitor *);
+
+#endif //MONITOR_H
Index: src/libcfa/concurrency/monitor.c
===================================================================
--- src/libcfa/concurrency/monitor.c	(revision 24cde55896b292c3bb610ade3c9b9286c0c7a9f9)
+++ src/libcfa/concurrency/monitor.c	(revision 24cde55896b292c3bb610ade3c9b9286c0c7a9f9)
@@ -0,0 +1,47 @@
+//                              -*- Mode: CFA -*-
+//
+// Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo
+//
+// The contents of this file are covered under the licence agreement in the
+// file "LICENCE" distributed with Cforall.
+//
+// monitor.c --
+//
+// Author           : Thierry Delisle
+// Created On       : Thd Feb 23 12:27:26 2017
+// Last Modified By : Thierry Delisle
+// Last Modified On : --
+// Update Count     : 0
+//
+
+#include "monitor"
+
+#include "kernel_private.h"
+
+void enter(monitor * this) {
+	lock( &this->lock );
+	thread * thrd = this_thread();
+
+	if( this->holder ) {
+		append( &this->entry_queue, thrd );
+		ScheduleInternal( &this->lock );
+		return;
+	}
+	else {
+		this->holder = thrd;
+	}
+
+	unlock( &this->lock );
+}
+
+void leave(monitor * this) {
+	lock( &this->lock );
+
+	thread * thrd = this_thread();
+	assert( thrd == this->holder );
+
+	this->holder = pop_head( &this->entry_queue );
+
+	unlock( &this->lock );
+	if( this->holder ) ScheduleThread( this->holder );
+}
Index: src/libcfa/concurrency/threads
===================================================================
--- src/libcfa/concurrency/threads	(revision ca1a5475f4eddc0c66780db2fd4589594588899b)
+++ src/libcfa/concurrency/threads	(revision 24cde55896b292c3bb610ade3c9b9286c0c7a9f9)
@@ -9,5 +9,5 @@
 //
 // Author           : Thierry Delisle
-// Created On       : Tue Jan 17 12:27:26 2016
+// Created On       : Tue Jan 17 12:27:26 2017
 // Last Modified By : Thierry Delisle
 // Last Modified On : --
Index: src/libcfa/concurrency/threads.c
===================================================================
--- src/libcfa/concurrency/threads.c	(revision ca1a5475f4eddc0c66780db2fd4589594588899b)
+++ src/libcfa/concurrency/threads.c	(revision 24cde55896b292c3bb610ade3c9b9286c0c7a9f9)
@@ -9,5 +9,5 @@
 //
 // Author           : Thierry Delisle
-// Created On       : Tue Jan 17 12:27:26 2016
+// Created On       : Tue Jan 17 12:27:26 2017
 // Last Modified By : Thierry Delisle
 // Last Modified On : --
Index: src/tests/.expect/monitor.txt
===================================================================
--- src/tests/.expect/monitor.txt	(revision 24cde55896b292c3bb610ade3c9b9286c0c7a9f9)
+++ src/tests/.expect/monitor.txt	(revision 24cde55896b292c3bb610ade3c9b9286c0c7a9f9)
@@ -0,0 +1,1 @@
+4000000
Index: src/tests/monitor.c
===================================================================
--- src/tests/monitor.c	(revision 24cde55896b292c3bb610ade3c9b9286c0c7a9f9)
+++ src/tests/monitor.c	(revision 24cde55896b292c3bb610ade3c9b9286c0c7a9f9)
@@ -0,0 +1,42 @@
+#include <fstream>
+#include <kernel>
+#include <monitor>
+#include <threads>
+
+struct global_t {
+	int value;
+	monitor m;
+};
+
+void ?{}(global_t * this) {
+	this->value = 0;
+}
+
+static global_t global;
+
+void increment( /*mutex*/ global_t * this ) {
+	enter( &this->m );
+	this->value += 1;
+	leave( &this->m );
+}
+
+struct MyThread { thread t; };
+
+DECL_THREAD(MyThread);
+
+void ?{}( MyThread * this ) {}
+
+void main( MyThread* this ) {
+	for(int i = 0; i < 1000000; i++) {
+		increment( &global );
+	}
+}
+
+int main(int argc, char* argv[]) {
+	assert( global.m.entry_queue.tail != NULL );
+	processor p;
+	{
+		scoped(MyThread) f[4];
+	}
+	sout | global.value | endl;
+}