From d04f95847832a71647610fcb9cfcef6c15b1b9e1 Mon Sep 17 00:00:00 2001
From: Alex Dutka <97711898+dutkalex@users.noreply.github.com>
Date: Fri, 25 Oct 2024 21:17:51 +0200
Subject: [PATCH] Update CMakeLists.txt

Enable CMAKE_{C,CXX}_STANDARD to be set on the command line, while still requiring C11 and C++17
---
 CMakeLists.txt | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index d04c785c09..c94ceaca0a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -46,11 +46,19 @@ if(NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
     "Debug" "Release" "RelWithDebInfo")
 endif()
 
-set( CMAKE_C_STANDARD 11 )
+if( NOT DEFINED CMAKE_C_STANDARD ) 
+  set( CMAKE_C_STANDARD 11 )
+elseif( CMAKE_C_STANDARD LESS 11 )
+  message( FATAL_ERROR "The CMAKE_C_STANDARD variable has been set to ${CMAKE_C_STANDARD}, but t8code requires C11" )
+endif()
 set( CMAKE_C_STANDARD_REQUIRED ON )
 set( CMAKE_C_EXTENSIONS OFF )
 
-set( CMAKE_CXX_STANDARD 17 )
+if( NOT DEFINED CMAKE_CXX_STANDARD ) 
+  set( CMAKE_CXX_STANDARD 17 )
+elseif( CMAKE_CXX_STANDARD LESS 17 )
+  message( FATAL_ERROR "The CMAKE_CXX_STANDARD variable has been set to ${CMAKE_CXX_STANDARD}, but t8code requires C++17" )
+endif()
 set( CMAKE_CXX_STANDARD_REQUIRED ON )
 set( CMAKE_CXX_EXTENSIONS OFF )