diff --git a/src/interfaces/libpq++/pgenv.h b/src/interfaces/libpq++/pgenv.h
index 136871cf7b..43068aacce 100644
--- a/src/interfaces/libpq++/pgenv.h
+++ b/src/interfaces/libpq++/pgenv.h
@@ -18,7 +18,7 @@
 #ifndef PGENV_H
 #define PGENV_H
 
-#include <string.h>
+#include <string>
 
 #ifdef __sun__
 #ifndef __GNUC__