score: Simplify yield and unblock scheduler ops

Update #2556.

11 files changed, 54 insertions, 79 deletions

diff --git a/cpukit/score/src/schedulercbsunblock.c b/cpukit/score/src/schedulercbsunblock.c
index 63abc12c70..be9696eed8 100644
--- a/cpukit/score/src/schedulercbsunblock.c
+++ b/cpukit/score/src/schedulercbsunblock.c
@@ -25,7 +25,7 @@
 #include <rtems/score/threadimpl.h>
 #include <rtems/score/watchdogimpl.h>
 
-Scheduler_Void_or_thread _Scheduler_CBS_Unblock(
+Scheduler_Void_or_bool _Scheduler_CBS_Unblock(
   const Scheduler_Control *scheduler,
   Thread_Control          *the_thread,
   Scheduler_Node          *node
@@ -68,5 +68,5 @@ Scheduler_Void_or_thread _Scheduler_CBS_Unblock(
   }
 
   _Scheduler_EDF_Unblock( scheduler, the_thread, &the_node->Base.Base );
-  SCHEDULER_RETURN_VOID_OR_NULL;
+  SCHEDULER_RETURN_VOID_OR_BOOL;
 }
diff --git a/cpukit/score/src/scheduleredfunblock.c b/cpukit/score/src/scheduleredfunblock.c
index 5b3fbb3943..45653396af 100644
--- a/cpukit/score/src/scheduleredfunblock.c
+++ b/cpukit/score/src/scheduleredfunblock.c
@@ -22,7 +22,7 @@
 #include <rtems/score/schedulerimpl.h>
 #include <rtems/score/thread.h>
 
-Scheduler_Void_or_thread _Scheduler_EDF_Unblock(
+Scheduler_Void_or_bool _Scheduler_EDF_Unblock(
   const Scheduler_Control *scheduler,
   Thread_Control          *the_thread,
   Scheduler_Node          *node
@@ -60,5 +60,5 @@ Scheduler_Void_or_thread _Scheduler_EDF_Unblock(
     );
   }
 
-  SCHEDULER_RETURN_VOID_OR_NULL;
+  SCHEDULER_RETURN_VOID_OR_BOOL;
 }
diff --git a/cpukit/score/src/scheduleredfyield.c b/cpukit/score/src/scheduleredfyield.c
index a54b1f5c72..dfcb4d3569 100644
--- a/cpukit/score/src/scheduleredfyield.c
+++ b/cpukit/score/src/scheduleredfyield.c
@@ -21,7 +21,7 @@
 
 #include <rtems/score/scheduleredfimpl.h>
 
-Scheduler_Void_or_thread _Scheduler_EDF_Yield(
+Scheduler_Void_or_bool _Scheduler_EDF_Yield(
   const Scheduler_Control *scheduler,
   Thread_Control          *the_thread,
   Scheduler_Node          *node
@@ -37,5 +37,5 @@ Scheduler_Void_or_thread _Scheduler_EDF_Yield(
   _Scheduler_EDF_Enqueue( context, the_node, the_node->priority );
   _Scheduler_EDF_Schedule_body( scheduler, the_thread, true );
 
-  SCHEDULER_RETURN_VOID_OR_NULL;
+  SCHEDULER_RETURN_VOID_OR_BOOL;
 }
diff --git a/cpukit/score/src/schedulerpriorityaffinitysmp.c b/cpukit/score/src/schedulerpriorityaffinitysmp.c
index 9c8fd3cd51..3ca3b73f10 100644
--- a/cpukit/score/src/schedulerpriorityaffinitysmp.c
+++ b/cpukit/score/src/schedulerpriorityaffinitysmp.c
@@ -270,16 +270,14 @@ static Scheduler_Node * _Scheduler_priority_affinity_SMP_Get_lowest_scheduled(
  * _Scheduler_priority_affinity_SMP_Get_lowest_scheduled into
  * _Scheduler_SMP_Enqueue_ordered.
  */
-static Thread_Control *_Scheduler_priority_affinity_SMP_Enqueue_fifo(
+static bool _Scheduler_priority_affinity_SMP_Enqueue_fifo(
   Scheduler_Context *context,
-  Scheduler_Node    *node,
-  Thread_Control    *needs_help
+  Scheduler_Node    *node
 )
 {
   return _Scheduler_SMP_Enqueue_ordered(
     context,
     node,
-    needs_help,
     _Scheduler_priority_affinity_SMP_Insert_priority_fifo_order,
     _Scheduler_priority_SMP_Insert_ready_fifo,
     _Scheduler_SMP_Insert_scheduled_fifo,
@@ -354,14 +352,14 @@ static void _Scheduler_priority_affinity_SMP_Check_for_migrations(
 /*
  * This is the public scheduler specific Unblock operation.
  */
-Thread_Control *_Scheduler_priority_affinity_SMP_Unblock(
+bool _Scheduler_priority_affinity_SMP_Unblock(
   const Scheduler_Control *scheduler,
   Thread_Control          *thread,
   Scheduler_Node          *node
 )
 {
   Scheduler_Context *context = _Scheduler_Get_context( scheduler );
-  Thread_Control    *needs_help;
+  bool               needs_help;
 
   needs_help = _Scheduler_SMP_Unblock(
     context,
@@ -383,10 +381,9 @@ Thread_Control *_Scheduler_priority_affinity_SMP_Unblock(
  *  This is unique to this scheduler because it passes scheduler specific
  *  get_lowest_scheduled helper to _Scheduler_SMP_Enqueue_ordered.
  */
-static Thread_Control *_Scheduler_priority_affinity_SMP_Enqueue_ordered(
+static bool _Scheduler_priority_affinity_SMP_Enqueue_ordered(
   Scheduler_Context     *context,
   Scheduler_Node        *node,
-  Thread_Control        *needs_help,
   Chain_Node_order       order,
   Scheduler_SMP_Insert   insert_ready,
   Scheduler_SMP_Insert   insert_scheduled
@@ -395,7 +392,6 @@ static Thread_Control *_Scheduler_priority_affinity_SMP_Enqueue_ordered(
   return _Scheduler_SMP_Enqueue_ordered(
     context,
     node,
-    needs_help,
     order,
     insert_ready,
     insert_scheduled,
@@ -410,16 +406,14 @@ static Thread_Control *_Scheduler_priority_affinity_SMP_Enqueue_ordered(
  *  to _Scheduler_priority_affinity_SMP_Enqueue_ordered() which
  *  invokes a scheduler unique get_lowest_scheduled helper.
  */
-static Thread_Control *_Scheduler_priority_affinity_SMP_Enqueue_lifo(
+static bool _Scheduler_priority_affinity_SMP_Enqueue_lifo(
   Scheduler_Context *context,
-  Scheduler_Node    *node,
-  Thread_Control    *needs_help
+  Scheduler_Node    *node
 )
 {
   return _Scheduler_priority_affinity_SMP_Enqueue_ordered(
     context,
     node,
-    needs_help,
     _Scheduler_priority_affinity_SMP_Insert_priority_lifo_order,
     _Scheduler_priority_SMP_Insert_ready_lifo,
     _Scheduler_SMP_Insert_scheduled_lifo
@@ -431,8 +425,7 @@ static Thread_Control *_Scheduler_priority_affinity_SMP_Enqueue_lifo(
  * invoke _Scheduler_SMP_Enqueue_scheduled_ordered() with
  * this scheduler's get_highest_ready() helper.
  */
-static Thread_Control *
-_Scheduler_priority_affinity_SMP_Enqueue_scheduled_ordered(
+static bool _Scheduler_priority_affinity_SMP_Enqueue_scheduled_ordered(
   Scheduler_Context    *context,
   Scheduler_Node       *node,
   Chain_Node_order      order,
@@ -458,7 +451,7 @@ _Scheduler_priority_affinity_SMP_Enqueue_scheduled_ordered(
  *  to _Scheduler_priority_affinity_SMP_Enqueue_scheduled__ordered() which
  *  invokes a scheduler unique get_lowest_scheduled helper.
  */
-static Thread_Control *_Scheduler_priority_affinity_SMP_Enqueue_scheduled_lifo(
+static bool _Scheduler_priority_affinity_SMP_Enqueue_scheduled_lifo(
   Scheduler_Context *context,
   Scheduler_Node    *node
 )
@@ -477,7 +470,7 @@ static Thread_Control *_Scheduler_priority_affinity_SMP_Enqueue_scheduled_lifo(
  *  to _Scheduler_priority_affinity_SMP_Enqueue_scheduled__ordered() which
  *  invokes a scheduler unique get_lowest_scheduled helper.
  */
-static Thread_Control *_Scheduler_priority_affinity_SMP_Enqueue_scheduled_fifo(
+static bool _Scheduler_priority_affinity_SMP_Enqueue_scheduled_fifo(
   Scheduler_Context *context,
   Scheduler_Node    *node
 )
diff --git a/cpukit/score/src/schedulerprioritysmp.c b/cpukit/score/src/schedulerprioritysmp.c
index fac2b6da7e..79b3d597a8 100644
--- a/cpukit/score/src/schedulerprioritysmp.c
+++ b/cpukit/score/src/schedulerprioritysmp.c
@@ -109,10 +109,9 @@ void _Scheduler_priority_SMP_Block(
   );
 }
 
-static Thread_Control *_Scheduler_priority_SMP_Enqueue_ordered(
+static bool _Scheduler_priority_SMP_Enqueue_ordered(
   Scheduler_Context    *context,
   Scheduler_Node       *node,
-  Thread_Control       *needs_help,
   Chain_Node_order      order,
   Scheduler_SMP_Insert  insert_ready,
   Scheduler_SMP_Insert  insert_scheduled
@@ -121,7 +120,6 @@ static Thread_Control *_Scheduler_priority_SMP_Enqueue_ordered(
   return _Scheduler_SMP_Enqueue_ordered(
     context,
     node,
-    needs_help,
     order,
     insert_ready,
     insert_scheduled,
@@ -131,39 +129,35 @@ static Thread_Control *_Scheduler_priority_SMP_Enqueue_ordered(
   );
 }
 
-static Thread_Control *_Scheduler_priority_SMP_Enqueue_lifo(
+static bool _Scheduler_priority_SMP_Enqueue_lifo(
   Scheduler_Context *context,
-  Scheduler_Node    *node,
-  Thread_Control    *needs_help
+  Scheduler_Node    *node
 )
 {
   return _Scheduler_priority_SMP_Enqueue_ordered(
     context,
     node,
-    needs_help,
     _Scheduler_SMP_Insert_priority_lifo_order,
     _Scheduler_priority_SMP_Insert_ready_lifo,
     _Scheduler_SMP_Insert_scheduled_lifo
   );
 }
 
-static Thread_Control *_Scheduler_priority_SMP_Enqueue_fifo(
+static bool _Scheduler_priority_SMP_Enqueue_fifo(
   Scheduler_Context *context,
-  Scheduler_Node    *node,
-  Thread_Control    *needs_help
+  Scheduler_Node    *node
 )
 {
   return _Scheduler_priority_SMP_Enqueue_ordered(
     context,
     node,
-    needs_help,
     _Scheduler_SMP_Insert_priority_fifo_order,
     _Scheduler_priority_SMP_Insert_ready_fifo,
     _Scheduler_SMP_Insert_scheduled_fifo
   );
 }
 
-static Thread_Control *_Scheduler_priority_SMP_Enqueue_scheduled_ordered(
+static bool _Scheduler_priority_SMP_Enqueue_scheduled_ordered(
   Scheduler_Context *context,
   Scheduler_Node *node,
   Chain_Node_order order,
@@ -184,7 +178,7 @@ static Thread_Control *_Scheduler_priority_SMP_Enqueue_scheduled_ordered(
   );
 }
 
-static Thread_Control *_Scheduler_priority_SMP_Enqueue_scheduled_lifo(
+static bool _Scheduler_priority_SMP_Enqueue_scheduled_lifo(
   Scheduler_Context *context,
   Scheduler_Node *node
 )
@@ -198,7 +192,7 @@ static Thread_Control *_Scheduler_priority_SMP_Enqueue_scheduled_lifo(
   );
 }
 
-static Thread_Control *_Scheduler_priority_SMP_Enqueue_scheduled_fifo(
+static bool _Scheduler_priority_SMP_Enqueue_scheduled_fifo(
   Scheduler_Context *context,
   Scheduler_Node *node
 )
@@ -212,7 +206,7 @@ static Thread_Control *_Scheduler_priority_SMP_Enqueue_scheduled_fifo(
   );
 }
 
-Thread_Control *_Scheduler_priority_SMP_Unblock(
+bool _Scheduler_priority_SMP_Unblock(
   const Scheduler_Control *scheduler,
   Thread_Control          *thread,
   Scheduler_Node          *node
@@ -318,7 +312,7 @@ void _Scheduler_priority_SMP_Withdraw_node(
   );
 }
 
-Thread_Control *_Scheduler_priority_SMP_Yield(
+bool _Scheduler_priority_SMP_Yield(
   const Scheduler_Control *scheduler,
   Thread_Control          *thread,
   Scheduler_Node          *node
diff --git a/cpukit/score/src/schedulerpriorityunblock.c b/cpukit/score/src/schedulerpriorityunblock.c
index 99d4310a4c..405b83f350 100644
--- a/cpukit/score/src/schedulerpriorityunblock.c
+++ b/cpukit/score/src/schedulerpriorityunblock.c
@@ -22,7 +22,7 @@
 
 #include <rtems/score/schedulerpriorityimpl.h>
 
-Scheduler_Void_or_thread _Scheduler_priority_Unblock (
+Scheduler_Void_or_bool _Scheduler_priority_Unblock (
   const Scheduler_Control *scheduler,
   Thread_Control          *the_thread,
   Scheduler_Node          *node
@@ -72,5 +72,5 @@ Scheduler_Void_or_thread _Scheduler_priority_Unblock (
     _Scheduler_Update_heir( the_thread, priority == PRIORITY_PSEUDO_ISR );
   }
 
-  SCHEDULER_RETURN_VOID_OR_NULL;
+  SCHEDULER_RETURN_VOID_OR_BOOL;
 }
diff --git a/cpukit/score/src/schedulerpriorityyield.c b/cpukit/score/src/schedulerpriorityyield.c
index 4d22dc9b4d..439877d0ce 100644
--- a/cpukit/score/src/schedulerpriorityyield.c
+++ b/cpukit/score/src/schedulerpriorityyield.c
@@ -21,7 +21,7 @@
 #include <rtems/score/schedulerpriorityimpl.h>
 #include <rtems/score/threadimpl.h>
 
-Scheduler_Void_or_thread _Scheduler_priority_Yield(
+Scheduler_Void_or_bool _Scheduler_priority_Yield(
   const Scheduler_Control *scheduler,
   Thread_Control          *the_thread,
   Scheduler_Node          *node
@@ -40,5 +40,5 @@ Scheduler_Void_or_thread _Scheduler_priority_Yield(
 
   _Scheduler_priority_Schedule_body( scheduler, the_thread, true );
 
-  SCHEDULER_RETURN_VOID_OR_NULL;
+  SCHEDULER_RETURN_VOID_OR_BOOL;
 }
diff --git a/cpukit/score/src/schedulersimplesmp.c b/cpukit/score/src/schedulersimplesmp.c
index ed2d5d1b73..392d4ff78a 100644
--- a/cpukit/score/src/schedulersimplesmp.c
+++ b/cpukit/score/src/schedulersimplesmp.c
@@ -176,10 +176,9 @@ void _Scheduler_simple_SMP_Block(
   );
 }
 
-static Thread_Control *_Scheduler_simple_SMP_Enqueue_ordered(
+static bool _Scheduler_simple_SMP_Enqueue_ordered(
   Scheduler_Context    *context,
   Scheduler_Node       *node,
-  Thread_Control       *needs_help,
   Chain_Node_order      order,
   Scheduler_SMP_Insert  insert_ready,
   Scheduler_SMP_Insert  insert_scheduled
@@ -188,7 +187,6 @@ static Thread_Control *_Scheduler_simple_SMP_Enqueue_ordered(
   return _Scheduler_SMP_Enqueue_ordered(
     context,
     node,
-    needs_help,
     order,
     insert_ready,
     insert_scheduled,
@@ -198,39 +196,35 @@ static Thread_Control *_Scheduler_simple_SMP_Enqueue_ordered(
   );
 }
 
-static Thread_Control *_Scheduler_simple_SMP_Enqueue_lifo(
+static bool _Scheduler_simple_SMP_Enqueue_lifo(
   Scheduler_Context *context,
-  Scheduler_Node    *node,
-  Thread_Control    *needs_help
+  Scheduler_Node    *node
 )
 {
   return _Scheduler_simple_SMP_Enqueue_ordered(
     context,
     node,
-    needs_help,
     _Scheduler_SMP_Insert_priority_lifo_order,
     _Scheduler_simple_SMP_Insert_ready_lifo,
     _Scheduler_SMP_Insert_scheduled_lifo
   );
 }
 
-static Thread_Control *_Scheduler_simple_SMP_Enqueue_fifo(
+static bool _Scheduler_simple_SMP_Enqueue_fifo(
   Scheduler_Context *context,
-  Scheduler_Node    *node,
-  Thread_Control    *needs_help
+  Scheduler_Node    *node
 )
 {
   return _Scheduler_simple_SMP_Enqueue_ordered(
     context,
     node,
-    needs_help,
     _Scheduler_SMP_Insert_priority_fifo_order,
     _Scheduler_simple_SMP_Insert_ready_fifo,
     _Scheduler_SMP_Insert_scheduled_fifo
   );
 }
 
-static Thread_Control *_Scheduler_simple_SMP_Enqueue_scheduled_ordered(
+static bool _Scheduler_simple_SMP_Enqueue_scheduled_ordered(
   Scheduler_Context *context,
   Scheduler_Node *node,
   Chain_Node_order order,
@@ -251,7 +245,7 @@ static Thread_Control *_Scheduler_simple_SMP_Enqueue_scheduled_ordered(
   );
 }
 
-static Thread_Control *_Scheduler_simple_SMP_Enqueue_scheduled_lifo(
+static bool _Scheduler_simple_SMP_Enqueue_scheduled_lifo(
   Scheduler_Context *context,
   Scheduler_Node *node
 )
@@ -265,7 +259,7 @@ static Thread_Control *_Scheduler_simple_SMP_Enqueue_scheduled_lifo(
   );
 }
 
-static Thread_Control *_Scheduler_simple_SMP_Enqueue_scheduled_fifo(
+static bool _Scheduler_simple_SMP_Enqueue_scheduled_fifo(
   Scheduler_Context *context,
   Scheduler_Node *node
 )
@@ -279,7 +273,7 @@ static Thread_Control *_Scheduler_simple_SMP_Enqueue_scheduled_fifo(
   );
 }
 
-Thread_Control *_Scheduler_simple_SMP_Unblock(
+bool _Scheduler_simple_SMP_Unblock(
   const Scheduler_Control *scheduler,
   Thread_Control          *thread,
   Scheduler_Node          *node
@@ -385,7 +379,7 @@ void _Scheduler_simple_SMP_Withdraw_node(
   );
 }
 
-Thread_Control *_Scheduler_simple_SMP_Yield(
+bool _Scheduler_simple_SMP_Yield(
   const Scheduler_Control *scheduler,
   Thread_Control          *thread,
   Scheduler_Node          *node
diff --git a/cpukit/score/src/schedulersimpleunblock.c b/cpukit/score/src/schedulersimpleunblock.c
index 5eeaf6cc35..fe02ece5b2 100644
--- a/cpukit/score/src/schedulersimpleunblock.c
+++ b/cpukit/score/src/schedulersimpleunblock.c
@@ -21,7 +21,7 @@
 #include <rtems/score/schedulersimpleimpl.h>
 #include <rtems/score/thread.h>
 
-Scheduler_Void_or_thread _Scheduler_simple_Unblock(
+Scheduler_Void_or_bool _Scheduler_simple_Unblock(
   const Scheduler_Control *scheduler,
   Thread_Control          *the_thread,
   Scheduler_Node          *node
@@ -55,5 +55,5 @@ Scheduler_Void_or_thread _Scheduler_simple_Unblock(
     );
   }
 
-  SCHEDULER_RETURN_VOID_OR_NULL;
+  SCHEDULER_RETURN_VOID_OR_BOOL;
 }
diff --git a/cpukit/score/src/schedulersimpleyield.c b/cpukit/score/src/schedulersimpleyield.c
index cfd123fb8c..c84f571933 100644
--- a/cpukit/score/src/schedulersimpleyield.c
+++ b/cpukit/score/src/schedulersimpleyield.c
@@ -20,7 +20,7 @@
 
 #include <rtems/score/schedulersimpleimpl.h>
 
-Scheduler_Void_or_thread _Scheduler_simple_Yield(
+Scheduler_Void_or_bool _Scheduler_simple_Yield(
   const Scheduler_Control *scheduler,
   Thread_Control          *the_thread,
   Scheduler_Node          *node
@@ -35,5 +35,5 @@ Scheduler_Void_or_thread _Scheduler_simple_Yield(
   _Scheduler_simple_Insert_priority_fifo( &context->Ready, the_thread );
   _Scheduler_simple_Schedule_body( scheduler, the_thread, false );
 
-  SCHEDULER_RETURN_VOID_OR_NULL;
+  SCHEDULER_RETURN_VOID_OR_BOOL;
 }
diff --git a/cpukit/score/src/schedulerstrongapa.c b/cpukit/score/src/schedulerstrongapa.c
index fce4541aa4..eaa352e793 100644
--- a/cpukit/score/src/schedulerstrongapa.c
+++ b/cpukit/score/src/schedulerstrongapa.c
@@ -235,10 +235,9 @@ void _Scheduler_strong_APA_Block(
   );
 }
 
-static Thread_Control *_Scheduler_strong_APA_Enqueue_ordered(
+static bool _Scheduler_strong_APA_Enqueue_ordered(
   Scheduler_Context    *context,
   Scheduler_Node       *node,
-  Thread_Control       *needs_help,
   Chain_Node_order      order,
   Scheduler_SMP_Insert  insert_ready,
   Scheduler_SMP_Insert  insert_scheduled
@@ -247,7 +246,6 @@ static Thread_Control *_Scheduler_strong_APA_Enqueue_ordered(
   return _Scheduler_SMP_Enqueue_ordered(
     context,
     node,
-    needs_help,
     order,
     insert_ready,
     insert_scheduled,
@@ -257,39 +255,35 @@ static Thread_Control *_Scheduler_strong_APA_Enqueue_ordered(
   );
 }
 
-static Thread_Control *_Scheduler_strong_APA_Enqueue_lifo(
+static bool _Scheduler_strong_APA_Enqueue_lifo(
   Scheduler_Context *context,
-  Scheduler_Node    *node,
-  Thread_Control    *needs_help
+  Scheduler_Node    *node
 )
 {
   return _Scheduler_strong_APA_Enqueue_ordered(
     context,
     node,
-    needs_help,
     _Scheduler_SMP_Insert_priority_lifo_order,
     _Scheduler_strong_APA_Insert_ready_lifo,
     _Scheduler_SMP_Insert_scheduled_lifo
   );
 }
 
-static Thread_Control *_Scheduler_strong_APA_Enqueue_fifo(
+static bool _Scheduler_strong_APA_Enqueue_fifo(
   Scheduler_Context *context,
-  Scheduler_Node    *node,
-  Thread_Control    *needs_help
+  Scheduler_Node    *node
 )
 {
   return _Scheduler_strong_APA_Enqueue_ordered(
     context,
     node,
-    needs_help,
     _Scheduler_SMP_Insert_priority_fifo_order,
     _Scheduler_strong_APA_Insert_ready_fifo,
     _Scheduler_SMP_Insert_scheduled_fifo
   );
 }
 
-static Thread_Control *_Scheduler_strong_APA_Enqueue_scheduled_ordered(
+static bool _Scheduler_strong_APA_Enqueue_scheduled_ordered(
   Scheduler_Context    *context,
   Scheduler_Node       *node,
   Chain_Node_order      order,
@@ -310,7 +304,7 @@ static Thread_Control *_Scheduler_strong_APA_Enqueue_scheduled_ordered(
   );
 }
 
-static Thread_Control *_Scheduler_strong_APA_Enqueue_scheduled_lifo(
+static bool _Scheduler_strong_APA_Enqueue_scheduled_lifo(
   Scheduler_Context *context,
   Scheduler_Node    *node
 )
@@ -324,7 +318,7 @@ static Thread_Control *_Scheduler_strong_APA_Enqueue_scheduled_lifo(
   );
 }
 
-static Thread_Control *_Scheduler_strong_APA_Enqueue_scheduled_fifo(
+static bool _Scheduler_strong_APA_Enqueue_scheduled_fifo(
   Scheduler_Context *context,
   Scheduler_Node    *node
 )
@@ -338,7 +332,7 @@ static Thread_Control *_Scheduler_strong_APA_Enqueue_scheduled_fifo(
   );
 }
 
-Thread_Control *_Scheduler_strong_APA_Unblock(
+bool _Scheduler_strong_APA_Unblock(
   const Scheduler_Control *scheduler,
   Thread_Control          *the_thread,
   Scheduler_Node          *node
@@ -444,7 +438,7 @@ void _Scheduler_strong_APA_Withdraw_node(
   );
 }
 
-Thread_Control *_Scheduler_strong_APA_Yield(
+bool _Scheduler_strong_APA_Yield(
   const Scheduler_Control *scheduler,
   Thread_Control          *the_thread,
   Scheduler_Node          *node