diff --git a/src/realm/util/cli_args.cpp b/src/realm/util/cli_args.cpp
index a199b2e..44455d0 100644
--- a/src/realm/util/cli_args.cpp
+++ b/src/realm/util/cli_args.cpp
@@ -3,6 +3,7 @@
 #include <algorithm>
 #include <cerrno>
 #include <cstdint>
+#include <cstdlib>
 #include <string>
 
 namespace realm::util {