diff --git a/bin/cmake_use_gcc_11.sh b/bin/cmake_use_gcc_11.sh
new file mode 100644
index 0000000..f1025d8
--- /dev/null
+++ b/bin/cmake_use_gcc_11.sh
@@ -0,0 +1,5 @@
+# if on macos use brew to install older g++
+# brew install gcc@11
+#
+# then use this cmake command to setup the Makefile to use the older version
+cmake .. -DCMAKE_CXX_COMPILER=/opt/homebrew/bin/g++-11 -DCMAKE_C_COMPILER=/opt/homebrew/bin/gcc-11