1 files changed, 22 insertions, 18 deletions

diff --git a/boost/thread/executors/loop_executor.hpp b/boost/thread/executors/loop_executor.hpp
index b08ff76f57..aee7a8d477 100644
--- a/boost/thread/executors/loop_executor.hpp
+++ b/boost/thread/executors/loop_executor.hpp
@@ -16,6 +16,7 @@
 #include <boost/thread/detail/move.hpp>
 #include <boost/thread/concurrent_queues/sync_queue.hpp>
 #include <boost/thread/executors/work.hpp>
+#include <boost/assert.hpp>
 
 #include <boost/config/abi_prefix.hpp>
 
@@ -41,14 +42,32 @@ namespace executors
      */
     bool try_executing_one()
     {
+      return execute_one(/*wait:*/false);
+    }
+
+  private:
+    /**
+     * Effects: Execute one task.
+     * Remark: If wait is true, waits until a task is available or the executor
+     *         is closed. If wait is false, returns false immediately if no
+     *         task is available.
+     * Returns: whether a task has been executed (if wait is true, only returns false if closed).
+     * Throws: whatever the current task constructor throws or the task() throws.
+     */
+    bool execute_one(bool wait)
+    {
       work task;
       try
       {
-        if (work_queue.try_pull(task) == queue_op_status::success)
+        queue_op_status status = wait ?
+          work_queue.wait_pull(task) :
+          work_queue.try_pull(task);
+        if (status == queue_op_status::success)
         {
           task();
           return true;
         }
+        BOOST_ASSERT(!wait || status == queue_op_status::closed);
         return false;
       }
       catch (...)
@@ -57,21 +76,6 @@ namespace executors
         //return false;
       }
     }
-  private:
-    /**
-     * Effects: schedule one task or yields
-     * Throws: whatever the current task constructor throws or the task() throws.
-     */
-    void schedule_one_or_yield()
-    {
-        if ( ! try_executing_one())
-        {
-          this_thread::yield();
-        }
-    }
-
-
-
 
   public:
     /// loop_executor is not copyable.
@@ -101,10 +105,10 @@ namespace executors
      */
     void loop()
     {
-      while (!closed())
+      while (execute_one(/*wait:*/true))
       {
-        schedule_one_or_yield();
       }
+      BOOST_ASSERT(closed());
       while (try_executing_one())
       {
       }