diff --git a/wrap/callback.h b/wrap/callback.h
index 77d12317..4ad7db2a 100644
--- a/wrap/callback.h
+++ b/wrap/callback.h
@@ -27,6 +27,7 @@
 #include <stdarg.h>  // For va_start, etc.
 #include <memory>    // For std::unique_ptr
 #include <iostream>
+#include <string.h>
 
 namespace vcg {
 /*! \brief This function allow lenghty algorithms to report progress and status.