diff --git a/regressions/ck_epoch/validate/ck_epoch_poll.c b/regressions/ck_epoch/validate/ck_epoch_poll.c
index 5a87293..b198eaa 100644
--- a/regressions/ck_epoch/validate/ck_epoch_poll.c
+++ b/regressions/ck_epoch/validate/ck_epoch_poll.c
@@ -39,6 +39,7 @@
 #include <ck_pr.h>
 #include <stdbool.h>
 #include <stddef.h>
+#include <string.h>
 #include <ck_epoch.h>
 #include <ck_stack.h>
 
diff --git a/regressions/ck_epoch/validate/ck_epoch_synchronize.c b/regressions/ck_epoch/validate/ck_epoch_synchronize.c
index fcc2a20..4c13b91 100644
--- a/regressions/ck_epoch/validate/ck_epoch_synchronize.c
+++ b/regressions/ck_epoch/validate/ck_epoch_synchronize.c
@@ -39,6 +39,7 @@
 #include <ck_pr.h>
 #include <stdbool.h>
 #include <stddef.h>
+#include <string.h>
 #include <ck_epoch.h>
 #include <ck_stack.h>