before pull

tsung-wei-huang · tsung-wei-huang · commit ae238f539817 · 2018-08-27T15:05:38.000-05:00
Merge branch 'subflow' of https://github.com/cpp-taskflow/cpp-taskflow into subflow
diff --git a/taskflow/taskflow.hpp b/taskflow/taskflow.hpp
@@ -38,6 +38,7 @@
 #include <numeric>
 #include <iomanip>
 #include <cassert>
+#include <optional>
 
 // Clang mis-interprets variant's get as a non-friend of variant and cannot
 // get compiled correctly. We use the patch: 
