diff --git a/callgrind/events.h b/callgrind/events.h
index 322d27f..0293043 100644
--- a/callgrind/events.h
+++ b/callgrind/events.h
@@ -121,9 +121,13 @@
 /* Allocate space for an event mapping */
 EventMapping* CLG_(get_eventmapping)(EventSet*);
 void CLG_(append_event)(EventMapping*, const HChar*);
-/* Returns number of characters written */
-Int CLG_(sprint_eventmapping)(HChar* buf, EventMapping*);
-/* Returns number of characters written */
-Int CLG_(sprint_mappingcost)(HChar* buf, EventMapping*, ULong*);
+/* Returns event mapping as a character string. That string is dynamically
+   allocated and it is the caller's responsibility to free it.
+   The function never returns NULL. */
+HChar *CLG_(eventmapping_as_string)(const EventMapping*);
+/* Returns mapping cost as a character string. That string is dynamically
+   allocated and it is the caller's responsibility to free it.
+   The function never returns NULL. */
+HChar *CLG_(mappingcost_as_string)(const EventMapping*, const ULong*);
 
 #endif /* CLG_EVENTS */