Index: uspace/lib/c/include/ipc/taskman.h
===================================================================
--- uspace/lib/c/include/ipc/taskman.h	(revision b22b0a94b341e922fce473e92cec4901af1e7086)
+++ uspace/lib/c/include/ipc/taskman.h	(revision c675ab1ebb159b7e38a64765f63096588f7d9ff1)
@@ -41,6 +41,11 @@
 typedef enum {
 	TASKMAN_WAIT = IPC_FIRST_USER_METHOD,
-	TASKMAN_RETVAL
+	TASKMAN_RETVAL,
+	TASKMAN_EVENT_CALLBACK
 } taskman_request_t;
+
+typedef enum {
+	TASKMAN_EV_TASK = IPC_FIRST_USER_METHOD
+} taskman_event_t;
 
 typedef enum {
Index: uspace/lib/c/include/task.h
===================================================================
--- uspace/lib/c/include/task.h	(revision b22b0a94b341e922fce473e92cec4901af1e7086)
+++ uspace/lib/c/include/task.h	(revision c675ab1ebb159b7e38a64765f63096588f7d9ff1)
@@ -75,5 +75,5 @@
 
 extern errno_t task_retval(int);
-extern void task_set_event_handler(task_event_handler_t);
+extern int task_register_event_handler(task_event_handler_t);
 
 #endif