diff --git a/test_conformance/basic/test_int2fp.cpp b/test_conformance/basic/test_int2fp.cpp
index 8b1203a7..dd5cc9a1 100644
--- a/test_conformance/basic/test_int2fp.cpp
+++ b/test_conformance/basic/test_int2fp.cpp
@@ -25,6 +25,7 @@
 #include <sys/stat.h>
 
 #include <algorithm>
+#include <cstdint>
 #include <map>
 #include <vector>