diff --git a/share/fast_io/fast_io.cppm b/share/fast_io/fast_io.cppm
index eb1b104c..467bb197 100644
--- a/share/fast_io/fast_io.cppm
+++ b/share/fast_io/fast_io.cppm
@@ -5,6 +5,7 @@ module;
 #include <fast_io_device.h>
 #include <fast_io_dsal/array.h>
 #include <fast_io_dsal/vector.h>
+#include <fast_io_dsal/string.h>
 
 #if !(((__STDC_HOSTED__ == 1 && (!defined(_GLIBCXX_HOSTED) || _GLIBCXX_HOSTED == 1) && \
 		!defined(_LIBCPP_FREESTANDING)) ||                                             \