Index: openacs-4/packages/openacs-default-theme/tcl/theme-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/openacs-default-theme/tcl/theme-procs.tcl,v
diff -u -N
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ openacs-4/packages/openacs-default-theme/tcl/theme-procs.tcl	7 Aug 2017 23:48:13 -0000	1.2
@@ -0,0 +1,25 @@
+ad_library {
+
+    Provides a simple API theme interactions
+    
+    @author Gustaf Neumann
+    @creation-date 05 July 2015
+}
+
+
+ad_proc -public -callback subsite::theme_changed -impl openacs-default-theme {
+    -subsite_id:required
+    -old_theme:required
+    -new_theme:required
+} {
+
+    Implementation of the theme_changed callback which is called, whenever a theme is changed
+    
+    @param subsite_id subsite, of which the theme was changed
+    @param old_theme the name of the old theme
+    @param new_theme the name of the new theme
+} {
+    ns_log notice "openacs-default-theme: theme of subsite $subsite_id changed from $old_theme to $new_theme"
+}
+
+