diff --git a/PIPMacros.cmake b/PIPMacros.cmake
index 5284fec1..5036e2fa 100644
--- a/PIPMacros.cmake
+++ b/PIPMacros.cmake
@@ -19,6 +19,11 @@ macro(PIP_EXTRACT_OPTIONS _pip_files _pip_options _abs)
 	endforeach()
 endmacro()
 
+
+# usage: pip_code_model(<out_var> file0 [file1 ...] [OPTIONS opt0 [opt1 ...]] [ABSOLUTE])
+# options you can see by exec "pip_cmg -h"
+# if not ABSOLUTE source files will be prepended by CMAKE_CURRENT_SOURCE_DIR
+# add ${<out_var>} to your target
 macro(pip_code_model RESULT)
 	PIP_EXTRACT_OPTIONS(CCM_SRC OPTS ABS ${ARGN})
 	#message(STATUS "src = ${CCM_SRC}")