damned picky clang

diff --git a/include/simgrid/s4u/Io.hpp b/include/simgrid/s4u/Io.hpp
index 2b82161..3e98128 100644 (file)
--- a/include/simgrid/s4u/Io.hpp
+++ b/include/simgrid/s4u/Io.hpp
@@ -10,6 +10,7 @@
 #include <simgrid/s4u/Activity.hpp>
 
 #include <atomic>
+#include <string>
 
 namespace simgrid {
 namespace s4u {