Add a copy operator to Mutex so that it can be used in class with an operator=.

diff --git a/include/deal.II/base/thread_management.h b/include/deal.II/base/thread_management.h
index 4c61e272b3decda843b6458958ad69eff36b2750..e975b972892d31fad6e5ced97804232fd7d7a5c8 100644 (file)
--- a/include/deal.II/base/thread_management.h
+++ b/include/deal.II/base/thread_management.h
@@ -304,6 +304,16 @@ namespace Threads
     {}
 
 
+    /**
+     * Copy operators. As discussed in this class's documentation, no state
+     * is copied from the object given as argument.
+     */
+    Mutex &operator = (const Mutex &)
+    {
+      return *this;
+    }
+
+
     /**
      * Acquire a mutex.
      */