diff --git a/tests/unit/test_hang.c b/tests/unit/test_hang.c
index 4ac18ec3..16a61d4f 100644
--- a/tests/unit/test_hang.c
+++ b/tests/unit/test_hang.c
@@ -5,6 +5,7 @@
 
 #include "unicorn_test.h"
 #include <stdio.h>
+#include <inttypes.h>
 
 uint64_t trunc_page(uint64_t addr)
 {
@@ -87,8 +88,8 @@ void test_hang(void **state)
 	uc_reg_read(uc, UC_ARM64_REG_X0, &x0);
 	uc_reg_read(uc, UC_ARM64_REG_X1, &x1);
 
-	printf("x0: %#lx\n", x0);
-	printf("x1: %#lx\n", x1);
+	printf("x0: %"PRIx64"\n", x0);
+	printf("x1: %"PRIx64"\n", x1);
 }
 
 int main(int argc, const char * argv[]) {