diff --git a/TODO b/TODO
index e330d46a959..263dce27e70 100644
--- a/TODO
+++ b/TODO
@@ -1530,7 +1530,18 @@ o Libraries (libc/, libm/)
   Description: There are many things implemented within the kernel (for example
                under sched/pthread) that probably should be migrated in the
                C library where it belongs.
-  Status:      Ope
+
+               I would really like to see a little flavor of a micro-kernel
+               at the OS interface:  I would like to see more primitive OS
+               system calls with more higher level logic in the C library.
+
+               One awkard thing is the incompatibility of KERNEL vs FLAT
+               builds:  In the kernel build, it would be nice to move many
+               of the thread-specific data items out of the TCB and into
+               the process address environment where they belong.  It is
+               difficult to make this compatible with the FLAT build,
+               however.
+  Status:      Open
   Priority:    Low
 
 o File system / Generic drivers (fs/, drivers/)
diff --git a/include/sys/syscall.h b/include/sys/syscall.h
index 5c13ec70e3a..0890ff66e38 100644
--- a/include/sys/syscall.h
+++ b/include/sys/syscall.h
@@ -401,17 +401,19 @@
 #  define SYS_pthread_mutex_unlock     (__SYS_pthread+21)
 #  define SYS_pthread_once             (__SYS_pthread+22)
 #  define SYS_pthread_setcancelstate   (__SYS_pthread+23)
-#  define SYS_pthread_setschedparam    (__SYS_pthread+24)
-#  define SYS_pthread_setschedprio     (__SYS_pthread+25)
-#  define SYS_pthread_setspecific      (__SYS_pthread+26)
-#  define SYS_pthread_yield            (__SYS_pthread+27)
+#  define SYS_Pthread_setcanceltype    (__SYS_pthread+24)
+#  define SYS_pthread_setschedparam    (__SYS_pthread+25)
+#  define SYS_pthread_setschedprio     (__SYS_pthread+26)
+#  define SYS_pthread_setspecific      (__SYS_pthread+27)
+#  define SYS_pthread_testcancel       (__SYS_pthread+28)
+#  define SYS_pthread_yield            (__SYS_pthread+29)
 
 #  ifdef CONFIG_SMP
-#    define SYS_pthread_setaffinity_np (__SYS_pthread+28)
-#    define SYS_pthread_getaffinity_np (__SYS_pthread+29)
-#    define __SYS_pthread_signals      (__SYS_pthread+30)
+#    define SYS_pthread_setaffinity_np (__SYS_pthread+30)
+#    define SYS_pthread_getaffinity_np (__SYS_pthread+31)
+#    define __SYS_pthread_signals      (__SYS_pthread+32)
 #  else
-#    define __SYS_pthread_signals      (__SYS_pthread+28)
+#    define __SYS_pthread_signals      (__SYS_pthread+30)
 #  endif
 
 #  ifndef CONFIG_DISABLE_SIGNALS
diff --git a/syscall/syscall.csv b/syscall/syscall.csv
index a28d0d01a65..e52159ab1d1 100644
--- a/syscall/syscall.csv
+++ b/syscall/syscall.csv
@@ -90,10 +90,12 @@
 "pthread_once","pthread.h","!defined(CONFIG_DISABLE_PTHREAD)","int","FAR pthread_once_t*","CODE void (*)(void)"
 "pthread_setaffinity_np","pthread.h","!defined(CONFIG_DISABLE_PTHREAD) && defined(CONFIG_SMP)","int","pthread_t","size_t","FAR const cpu_set_t*"
 "pthread_setcancelstate","pthread.h","!defined(CONFIG_DISABLE_PTHREAD)","int","int","FAR int*"
+"pthread_setcanceltype","pthread.h","!defined(CONFIG_DISABLE_PTHREAD)","int","int","FAR int*"
 "pthread_setschedparam","pthread.h","!defined(CONFIG_DISABLE_PTHREAD)","int","pthread_t","int","FAR const struct sched_param*"
 "pthread_setschedprio","pthread.h","!defined(CONFIG_DISABLE_PTHREAD)","int","pthread_t","int"
 "pthread_setspecific","pthread.h","!defined(CONFIG_DISABLE_PTHREAD)","int","pthread_key_t","FAR const void*"
 "pthread_sigmask","pthread.h","!defined(CONFIG_DISABLE_SIGNALS) && !defined(CONFIG_DISABLE_PTHREAD)","int","int","FAR const sigset_t*","FAR sigset_t*"
+"pthread_testcancel","pthread.h","!defined(CONFIG_DISABLE_PTHREAD)","void"
 "pthread_yield","pthread.h","!defined(CONFIG_DISABLE_PTHREAD)","void"
 "putenv","stdlib.h","!defined(CONFIG_DISABLE_ENVIRON)","int","FAR const char*"
 "read","unistd.h","CONFIG_NSOCKET_DESCRIPTORS > 0 || CONFIG_NFILE_DESCRIPTORS > 0","ssize_t","int","FAR void*","size_t"
diff --git a/syscall/syscall_lookup.h b/syscall/syscall_lookup.h
index 60f194fc203..a261bef9a71 100644
--- a/syscall/syscall_lookup.h
+++ b/syscall/syscall_lookup.h
@@ -291,9 +291,11 @@ SYSCALL_LOOKUP(up_assert,                 2, STUB_up_assert)
   SYSCALL_LOOKUP(pthread_mutex_unlock,    1, STUB_pthread_mutex_unlock)
   SYSCALL_LOOKUP(pthread_once,            2, STUB_pthread_once)
   SYSCALL_LOOKUP(pthread_setcancelstate,  2, STUB_pthread_setcancelstate)
+  SYSCALL_LOOKUP(pthread_setcanceltype,   2, STUB_pthread_setcanceltype)
   SYSCALL_LOOKUP(pthread_setschedparam,   3, STUB_pthread_setschedparam)
   SYSCALL_LOOKUP(pthread_setschedprio,    2, STUB_pthread_setschedprio)
   SYSCALL_LOOKUP(pthread_setspecific,     2, STUB_pthread_setspecific)
+  SYSCALL_LOOKUP(pthread_testcancel,      0, STUB_pthread_testcancel)
   SYSCALL_LOOKUP(pthread_yield,           0, STUB_pthread_yield)
 #  ifdef CONFIG_SMP
   SYSCALL_LOOKUP(pthread_setaffinity,     3, STUB_pthread_setaffinity)
diff --git a/syscall/syscall_stublookup.c b/syscall/syscall_stublookup.c
index 2b7b1eafca5..43e4ebfecb3 100644
--- a/syscall/syscall_stublookup.c
+++ b/syscall/syscall_stublookup.c
@@ -292,12 +292,15 @@ uintptr_t STUB_pthread_mutex_unlock(int nbr, uintptr_t parm1);
 uintptr_t STUB_pthread_once(int nbr, uintptr_t parm1, uintptr_t parm2);
 uintptr_t STUB_pthread_setcancelstate(int nbr, uintptr_t parm1,
             uintptr_t parm2);
+uintptr_t STUB_pthread_setcanceltype(int nbr, uintptr_t parm1,
+            uintptr_t parm2);
 uintptr_t STUB_pthread_setschedparam(int nbr, uintptr_t parm1,
             uintptr_t parm2, uintptr_t parm3);
 uintptr_t STUB_pthread_setschedprio(int nbr, uintptr_t parm1,
             uintptr_t parm2);
 uintptr_t STUB_pthread_setspecific(int nbr, uintptr_t parm1,
             uintptr_t parm2);
+uintptr_t STUB_pthread_testcancel(int nbr);
 uintptr_t STUB_pthread_yield(int nbr);
 
 uintptr_t STUB_pthread_setaffinity(int nbr, uintptr_t parm1,