diff --git a/include/dap_string.h b/include/dap_string.h
index cacb8d0d070e2f7a079f6820e71cb83983f761e2..7275f9db7599d6a24a8615c2cb75c18471dbb44f 100755
--- a/include/dap_string.h
+++ b/include/dap_string.h
@@ -6,6 +6,7 @@
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdint.h>
+#include <sys/types.h>
 
 typedef struct _dap_string dap_string_t;