diff --git a/demo/c++/README.md b/demo/c++/README.md
index d18d49ef4..daa4198c1 100644
--- a/demo/c++/README.md
+++ b/demo/c++/README.md
@@ -69,7 +69,7 @@ On OS X you can also create an xcode project:
 
 First you need to build the visual studio solution with gyp:
 
-    gyp rundemo.gyp --depth=. -f msvs -G msvs_version=2010
+    C:\Python27\python.exe c:\Python27\Scripts\gyp rundemo.gyp --depth=. -f msvs -G msvs_version=2010
 
 Then you can compile with `msbuild`:
 
@@ -78,4 +78,4 @@ Then you can compile with `msbuild`:
 Then run it!
 
     for /f %i in ('mapnik-config --prefix') do set MAPNIK_PREFIX=%i
-    Release\rundemo.exe %MAPNIK_PREFIX%
\ No newline at end of file
+    Release\rundemo.exe %MAPNIK_PREFIX%