Index: uspace/lib/c/include/ipc/event.h
===================================================================
--- uspace/lib/c/include/ipc/event.h	(revision 25a179efc4ecca45aa90793992b6c1c2743fd07f)
+++ uspace/lib/c/include/ipc/event.h	(revision 3b47db687606b55f2694aaa5c4c6db563b5b61eb)
@@ -39,10 +39,10 @@
 #include <types/common.h>
 
-extern int ipc_event_subscribe(event_type_t, sysarg_t);
-extern int ipc_event_task_subscribe(event_task_type_t, sysarg_t);
-extern int ipc_event_unsubscribe(event_type_t);
-extern int ipc_event_task_unsubscribe(event_task_type_t);
-extern int ipc_event_unmask(event_type_t);
-extern int ipc_event_task_unmask(event_task_type_t);
+extern errno_t ipc_event_subscribe(event_type_t, sysarg_t);
+extern errno_t ipc_event_task_subscribe(event_task_type_t, sysarg_t);
+extern errno_t ipc_event_unsubscribe(event_type_t);
+extern errno_t ipc_event_task_unsubscribe(event_task_type_t);
+extern errno_t ipc_event_unmask(event_type_t);
+extern errno_t ipc_event_task_unmask(event_task_type_t);
 
 #endif
Index: uspace/lib/c/include/ipc/ipc.h
===================================================================
--- uspace/lib/c/include/ipc/ipc.h	(revision 25a179efc4ecca45aa90793992b6c1c2743fd07f)
+++ uspace/lib/c/include/ipc/ipc.h	(revision 3b47db687606b55f2694aaa5c4c6db563b5b61eb)
@@ -46,7 +46,7 @@
 #include <abi/cap.h>
 
-typedef void (*ipc_async_callback_t)(void *, int, ipc_call_t *);
+typedef void (*ipc_async_callback_t)(void *, errno_t, ipc_call_t *);
 
-extern int ipc_wait_cycle(ipc_call_t *, sysarg_t, unsigned int);
+extern errno_t ipc_wait_cycle(ipc_call_t *, sysarg_t, unsigned int);
 extern void ipc_poke(void);
 
@@ -54,6 +54,6 @@
 	ipc_wait_for_call_timeout(data, SYNCH_NO_TIMEOUT);
 
-extern int ipc_wait_for_call_timeout(ipc_call_t *, sysarg_t);
-extern int ipc_trywait_for_call(ipc_call_t *);
+extern errno_t ipc_wait_for_call_timeout(ipc_call_t *, sysarg_t);
+extern errno_t ipc_trywait_for_call(ipc_call_t *);
 
 /*
@@ -78,7 +78,7 @@
 	    (arg5))
 
-extern int ipc_answer_fast(cap_handle_t, int, sysarg_t, sysarg_t,
+extern errno_t ipc_answer_fast(cap_handle_t, errno_t, sysarg_t, sysarg_t,
     sysarg_t, sysarg_t);
-extern int ipc_answer_slow(cap_handle_t, int, sysarg_t, sysarg_t,
+extern errno_t ipc_answer_slow(cap_handle_t, errno_t, sysarg_t, sysarg_t,
     sysarg_t, sysarg_t, sysarg_t);
 
@@ -115,12 +115,12 @@
     sysarg_t, sysarg_t, sysarg_t, void *, ipc_async_callback_t);
 
-extern int ipc_hangup(cap_handle_t);
+extern errno_t ipc_hangup(cap_handle_t);
 
-extern int ipc_forward_fast(cap_handle_t, cap_handle_t, sysarg_t, sysarg_t,
+extern errno_t ipc_forward_fast(cap_handle_t, cap_handle_t, sysarg_t, sysarg_t,
     sysarg_t, unsigned int);
-extern int ipc_forward_slow(cap_handle_t, cap_handle_t, sysarg_t, sysarg_t,
+extern errno_t ipc_forward_slow(cap_handle_t, cap_handle_t, sysarg_t, sysarg_t,
     sysarg_t, sysarg_t, sysarg_t, sysarg_t, unsigned int);
 
-extern int ipc_connect_kbox(task_id_t, cap_handle_t *);
+extern errno_t ipc_connect_kbox(task_id_t, cap_handle_t *);
 
 #endif
Index: uspace/lib/c/include/ipc/irq.h
===================================================================
--- uspace/lib/c/include/ipc/irq.h	(revision 25a179efc4ecca45aa90793992b6c1c2743fd07f)
+++ uspace/lib/c/include/ipc/irq.h	(revision 3b47db687606b55f2694aaa5c4c6db563b5b61eb)
@@ -40,6 +40,6 @@
 #include <abi/cap.h>
 
-extern int ipc_irq_subscribe(int, sysarg_t, const irq_code_t *, cap_handle_t *);
-extern int ipc_irq_unsubscribe(cap_handle_t);
+extern errno_t ipc_irq_subscribe(int, sysarg_t, const irq_code_t *, cap_handle_t *);
+extern errno_t ipc_irq_unsubscribe(cap_handle_t);
 
 #endif