diff --git a/c/qrcodegen-demo.c b/c/qrcodegen-demo.c
index a987521..43b08d6 100644
--- a/c/qrcodegen-demo.c
+++ b/c/qrcodegen-demo.c
@@ -25,6 +25,7 @@
  *   Software.
  */
 
+#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include "qrcodegen.h"
diff --git a/c/qrcodegen-test.c b/c/qrcodegen-test.c
index 822d7e9..1b9fd2e 100644
--- a/c/qrcodegen-test.c
+++ b/c/qrcodegen-test.c
@@ -27,6 +27,8 @@
 
 #include <assert.h>
 #include <limits.h>
+#include <stdbool.h>
+#include <stddef.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/c/qrcodegen.c b/c/qrcodegen.c
index 79206a0..7acd9d1 100644
--- a/c/qrcodegen.c
+++ b/c/qrcodegen.c
@@ -24,6 +24,7 @@
 
 #include <assert.h>
 #include <limits.h>
+#include <stddef.h>
 #include <stdlib.h>
 #include <string.h>
 #include "qrcodegen.h"