From b2b64700fb977bb3b340d3ce6a8c69dc29c2c330 Mon Sep 17 00:00:00 2001
From: Mateusz Pusz <mateusz.pusz@gmail.com>
Date: Mon, 10 Jun 2024 23:06:34 +0200
Subject: [PATCH] fix: missing `<functional>` header file added to
 `expression_template.h`

---
 src/core/include/mp-units/framework/expression_template.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/core/include/mp-units/framework/expression_template.h b/src/core/include/mp-units/framework/expression_template.h
index f84bce29..acdf953e 100644
--- a/src/core/include/mp-units/framework/expression_template.h
+++ b/src/core/include/mp-units/framework/expression_template.h
@@ -29,6 +29,7 @@
 
 #ifndef MP_UNITS_IN_MODULE_INTERFACE
 #include <cstdint>
+#include <functional>
 #endif
 
 namespace mp_units {