diff --git a/lib/formats/json_reserve.c b/lib/formats/json_reserve.c
index 58e0b77b3..b075dbe6a 100644
--- a/lib/formats/json_reserve.c
+++ b/lib/formats/json_reserve.c
@@ -20,6 +20,8 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  *********************************************************************************/
 
+#include <string.h>
+
 #include <villas/plugin.h>
 #include <villas/sample.h>
 #include <villas/node.h>
diff --git a/lib/hooks/print.c b/lib/hooks/print.c
index f32512b1b..ceae9037b 100644
--- a/lib/hooks/print.c
+++ b/lib/hooks/print.c
@@ -24,6 +24,8 @@
  * @{
  */
 
+#include <string.h>
+
 #include <villas/hook.h>
 #include <villas/plugin.h>
 #include <villas/path.h>