From a824b9a66abdc3a310df2118ff5913f4e1b0b07a Mon Sep 17 00:00:00 2001
From: kallaballa <amir@viel-zu.org>
Date: Thu, 13 Apr 2023 05:46:48 +0200
Subject: [PATCH] explicitely check for c++20 feature in cmake

---
 modules/viz2d/CMakeLists.txt | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/modules/viz2d/CMakeLists.txt b/modules/viz2d/CMakeLists.txt
index 7429cbcd6..cf47337cd 100644
--- a/modules/viz2d/CMakeLists.txt
+++ b/modules/viz2d/CMakeLists.txt
@@ -21,6 +21,13 @@ elseif(NOT nanogui_FOUND)
   ocv_module_disable(viz2d)
 endif()
 
+get_property(known_features GLOBAL PROPERTY CMAKE_CXX_KNOWN_FEATURES)
+list (FIND known_features "cxx_std_20" idx)
+if (${idx} LESS 0)
+  message(STATUS "Module opencv_viz2d disabled because it requires C++20")
+  ocv_module_disable(viz2d)
+endif()
+
 #  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -DVIZ2D_USE_ES3=1")
 
 include_directories(${glfw3_INCLUDE_DIRS})