diff --git a/src/imap.c b/src/imap.c
index b6314b7..0c89145 100644
--- a/src/imap.c
+++ b/src/imap.c
@@ -28,6 +28,7 @@
 #include <sys/select.h>
 #include <errno.h>
 #include <netdb.h>
+#include <string.h>
 #include <openssl/ssl.h>
 #include <openssl/err.h>
 
diff --git a/src/tls.c b/src/tls.c
index 1700fb5..7bbd3f4 100644
--- a/src/tls.c
+++ b/src/tls.c
@@ -28,6 +28,7 @@
 #include <sys/select.h>
 #include <errno.h>
 #include <netdb.h>
+#include <string.h>
 #include <openssl/ssl.h>
 #include <openssl/err.h>