diff -Naur a/include/sexp/sexp-error.h b/include/sexp/sexp-error.h
--- a/include/sexp/sexp-error.h	2023-04-19 15:01:09.000000000 +0300
+++ b/include/sexp/sexp-error.h	2023-05-03 10:25:42.872644722 +0300
@@ -29,6 +29,7 @@
 
 #pragma once
 
+#include <cstdint>
 #include <exception>
 #include <iostream>
 #include <string>