diff --git a/modules/fc.cmake b/modules/fc.cmake
index 55379a4..76dd071 100644
--- a/modules/fc.cmake
+++ b/modules/fc.cmake
@@ -5,10 +5,22 @@
 # If environment variable FCFLAGS is set, then the FCFLAGS are used
 # and no other flags are used or appended.
 #
-# Defines::
+# Environment variables used::
+#
+#   FCFLAGS
+#
+# CMake variables used::
+#
+#   EXTRA_FCFLAGS
+#
+# CMake variables defined::
 #
 #   CMAKE_Fortran_MODULE_DIRECTORY (${PROJECT_BINARY_DIR}/include/fortran)
 #
+# CMake variables modified::
+#
+#   CMAKE_Fortran_FLAGS
+#
 # Example autocmake.cfg entry::
 #
 #   [fc]