Index: kernel/generic/include/ipc/event.h
===================================================================
--- kernel/generic/include/ipc/event.h	(revision 7f11dc6ba31c85d4b1daa9c4ebd4d6f99082a87c)
+++ kernel/generic/include/ipc/event.h	(revision 847844a5c1c6014e479cb00bf10c9d740927aa2d)
@@ -95,12 +95,12 @@
 	event_task_notify((t), (e), (m), (a1), (a2), (a3), (a4), (a5))
 
-extern int event_notify(event_type_t, bool, sysarg_t, sysarg_t, sysarg_t,
+extern errno_t event_notify(event_type_t, bool, sysarg_t, sysarg_t, sysarg_t,
     sysarg_t, sysarg_t);
-extern int event_task_notify(struct task *, event_task_type_t, bool, sysarg_t, sysarg_t,
+extern errno_t event_task_notify(struct task *, event_task_type_t, bool, sysarg_t, sysarg_t,
     sysarg_t, sysarg_t, sysarg_t);
 
-extern sysarg_t sys_ipc_event_subscribe(sysarg_t, sysarg_t);
-extern sysarg_t sys_ipc_event_unsubscribe(sysarg_t);
-extern sysarg_t sys_ipc_event_unmask(sysarg_t);
+extern sys_errno_t sys_ipc_event_subscribe(sysarg_t, sysarg_t);
+extern sys_errno_t sys_ipc_event_unsubscribe(sysarg_t);
+extern sys_errno_t sys_ipc_event_unmask(sysarg_t);
 
 #endif
Index: kernel/generic/include/ipc/ipc.h
===================================================================
--- kernel/generic/include/ipc/ipc.h	(revision 7f11dc6ba31c85d4b1daa9c4ebd4d6f99082a87c)
+++ kernel/generic/include/ipc/ipc.h	(revision 847844a5c1c6014e479cb00bf10c9d740927aa2d)
@@ -186,8 +186,8 @@
 extern void ipc_call_release(call_t *);
 
-extern int ipc_call_sync(phone_t *, call_t *);
-extern int ipc_call(phone_t *, call_t *);
+extern errno_t ipc_call_sync(phone_t *, call_t *);
+extern errno_t ipc_call(phone_t *, call_t *);
 extern call_t *ipc_wait_for_call(answerbox_t *, uint32_t, unsigned int);
-extern int ipc_forward(call_t *, phone_t *, answerbox_t *, unsigned int);
+extern errno_t ipc_forward(call_t *, phone_t *, answerbox_t *, unsigned int);
 extern void ipc_answer(answerbox_t *, call_t *);
 extern void _ipc_answer_free_call(call_t *, bool);
@@ -195,10 +195,10 @@
 extern void ipc_phone_init(phone_t *, struct task *);
 extern bool ipc_phone_connect(phone_t *, answerbox_t *);
-extern int ipc_phone_hangup(phone_t *);
+extern errno_t ipc_phone_hangup(phone_t *);
 
 extern void ipc_answerbox_init(answerbox_t *, struct task *);
 
 extern void ipc_cleanup(void);
-extern void ipc_backsend_err(phone_t *, call_t *, int);
+extern void ipc_backsend_err(phone_t *, call_t *, errno_t);
 extern void ipc_answerbox_slam_phones(answerbox_t *, bool);
 extern void ipc_cleanup_call_list(answerbox_t *, list_t *);
Index: kernel/generic/include/ipc/ipcrsc.h
===================================================================
--- kernel/generic/include/ipc/ipcrsc.h	(revision 7f11dc6ba31c85d4b1daa9c4ebd4d6f99082a87c)
+++ kernel/generic/include/ipc/ipcrsc.h	(revision 847844a5c1c6014e479cb00bf10c9d740927aa2d)
@@ -40,5 +40,5 @@
 #include <cap/cap.h>
 
-extern int phone_alloc(task_t *, cap_handle_t *);
+extern errno_t phone_alloc(task_t *, cap_handle_t *);
 extern bool phone_connect(cap_handle_t, answerbox_t *);
 extern void phone_dealloc(cap_handle_t);
Index: kernel/generic/include/ipc/irq.h
===================================================================
--- kernel/generic/include/ipc/irq.h	(revision 7f11dc6ba31c85d4b1daa9c4ebd4d6f99082a87c)
+++ kernel/generic/include/ipc/irq.h	(revision 847844a5c1c6014e479cb00bf10c9d740927aa2d)
@@ -51,7 +51,7 @@
 extern void ipc_irq_top_half_handler(irq_t *);
 
-extern int ipc_irq_subscribe(answerbox_t *, inr_t, sysarg_t, irq_code_t *,
+extern errno_t ipc_irq_subscribe(answerbox_t *, inr_t, sysarg_t, irq_code_t *,
     cap_handle_t *);
-extern int ipc_irq_unsubscribe(answerbox_t *, int);
+extern errno_t ipc_irq_unsubscribe(answerbox_t *, int);
 
 /*
Index: kernel/generic/include/ipc/kbox.h
===================================================================
--- kernel/generic/include/ipc/kbox.h	(revision 7f11dc6ba31c85d4b1daa9c4ebd4d6f99082a87c)
+++ kernel/generic/include/ipc/kbox.h	(revision 847844a5c1c6014e479cb00bf10c9d740927aa2d)
@@ -50,5 +50,5 @@
 } kbox_t;
 
-extern int ipc_connect_kbox(task_id_t, cap_handle_t *);
+extern errno_t ipc_connect_kbox(task_id_t, cap_handle_t *);
 extern void ipc_kbox_cleanup(void);
 
Index: kernel/generic/include/ipc/sysipc.h
===================================================================
--- kernel/generic/include/ipc/sysipc.h	(revision 7f11dc6ba31c85d4b1daa9c4ebd4d6f99082a87c)
+++ kernel/generic/include/ipc/sysipc.h	(revision 847844a5c1c6014e479cb00bf10c9d740927aa2d)
@@ -40,24 +40,24 @@
 #include <typedefs.h>
 
-extern int ipc_req_internal(int, ipc_data_t *, sysarg_t);
+extern errno_t ipc_req_internal(int, ipc_data_t *, sysarg_t);
 
-extern sysarg_t sys_ipc_call_async_fast(sysarg_t, sysarg_t, sysarg_t,
+extern sys_errno_t sys_ipc_call_async_fast(sysarg_t, sysarg_t, sysarg_t,
     sysarg_t, sysarg_t, sysarg_t);
-extern sysarg_t sys_ipc_call_async_slow(sysarg_t, ipc_data_t *, sysarg_t);
-extern sysarg_t sys_ipc_answer_fast(sysarg_t, sysarg_t, sysarg_t, sysarg_t,
+extern sys_errno_t sys_ipc_call_async_slow(sysarg_t, ipc_data_t *, sysarg_t);
+extern sys_errno_t sys_ipc_answer_fast(sysarg_t, sysarg_t, sysarg_t, sysarg_t,
     sysarg_t, sysarg_t);
-extern sysarg_t sys_ipc_answer_slow(sysarg_t, ipc_data_t *);
-extern sysarg_t sys_ipc_wait_for_call(ipc_data_t *, uint32_t, unsigned int);
-extern sysarg_t sys_ipc_poke(void);
-extern sysarg_t sys_ipc_forward_fast(sysarg_t, sysarg_t, sysarg_t, sysarg_t,
+extern sys_errno_t sys_ipc_answer_slow(sysarg_t, ipc_data_t *);
+extern sys_errno_t sys_ipc_wait_for_call(ipc_data_t *, uint32_t, unsigned int);
+extern sys_errno_t sys_ipc_poke(void);
+extern sys_errno_t sys_ipc_forward_fast(sysarg_t, sysarg_t, sysarg_t, sysarg_t,
     sysarg_t, unsigned int);
-extern sysarg_t sys_ipc_forward_slow(sysarg_t, sysarg_t, ipc_data_t *,
+extern sys_errno_t sys_ipc_forward_slow(sysarg_t, sysarg_t, ipc_data_t *,
     unsigned int);
-extern sysarg_t sys_ipc_hangup(sysarg_t);
+extern sys_errno_t sys_ipc_hangup(sysarg_t);
 
-extern sysarg_t sys_ipc_irq_subscribe(inr_t, sysarg_t, irq_code_t *, cap_handle_t *);
-extern sysarg_t sys_ipc_irq_unsubscribe(sysarg_t);
+extern sys_errno_t sys_ipc_irq_subscribe(inr_t, sysarg_t, irq_code_t *, cap_handle_t *);
+extern sys_errno_t sys_ipc_irq_unsubscribe(sysarg_t);
 
-extern sysarg_t sys_ipc_connect_kbox(task_id_t *, cap_handle_t *);
+extern sys_errno_t sys_ipc_connect_kbox(task_id_t *, cap_handle_t *);
 
 #endif
Index: kernel/generic/include/ipc/sysipc_ops.h
===================================================================
--- kernel/generic/include/ipc/sysipc_ops.h	(revision 7f11dc6ba31c85d4b1daa9c4ebd4d6f99082a87c)
+++ kernel/generic/include/ipc/sysipc_ops.h	(revision 847844a5c1c6014e479cb00bf10c9d740927aa2d)
@@ -90,5 +90,5 @@
 	 * Invoked on:		all calls
 	 */
-	int (* request_preprocess)(call_t *, phone_t *);
+	errno_t (* request_preprocess)(call_t *, phone_t *);
 
 	/**
@@ -102,5 +102,5 @@
 	 * Invoked on:		all forgotten calls
 	 */	
-	int (* request_forget)(call_t *);
+	errno_t (* request_forget)(call_t *);
 
 	/**
@@ -123,5 +123,5 @@
 	 * Invoked on:		all forgotten calls
 	 */
-	int (* answer_cleanup)(call_t *, ipc_data_t *);
+	errno_t (* answer_cleanup)(call_t *, ipc_data_t *);
 
 	/**
@@ -134,5 +134,5 @@
 	 * Invoked on:		all answered calls
 	 */
-	int (* answer_preprocess)(call_t *, ipc_data_t *);
+	errno_t (* answer_preprocess)(call_t *, ipc_data_t *);
 
 	/**
@@ -144,15 +144,15 @@
 	 * Invoked on:		all answered calls
 	 */
-	int (* answer_process)(call_t *);
+	errno_t (* answer_process)(call_t *);
 } sysipc_ops_t;
 
 extern sysipc_ops_t *sysipc_ops_get(sysarg_t);
 
-extern int null_request_preprocess(call_t *, phone_t *);
-extern int null_request_forget(call_t *);
+extern errno_t null_request_preprocess(call_t *, phone_t *);
+extern errno_t null_request_forget(call_t *);
 extern int null_request_process(call_t *, answerbox_t *);
-extern int null_answer_cleanup(call_t *, ipc_data_t *);
-extern int null_answer_preprocess(call_t *, ipc_data_t *);
-extern int null_answer_process(call_t *);
+extern errno_t null_answer_cleanup(call_t *, ipc_data_t *);
+extern errno_t null_answer_preprocess(call_t *, ipc_data_t *);
+extern errno_t null_answer_process(call_t *);
 
 #endif
Index: kernel/generic/include/ipc/sysipc_priv.h
===================================================================
--- kernel/generic/include/ipc/sysipc_priv.h	(revision 7f11dc6ba31c85d4b1daa9c4ebd4d6f99082a87c)
+++ kernel/generic/include/ipc/sysipc_priv.h	(revision 847844a5c1c6014e479cb00bf10c9d740927aa2d)
@@ -38,5 +38,5 @@
 #include <ipc/ipc.h>
 
-extern int answer_preprocess(call_t *, ipc_data_t *);
+extern errno_t answer_preprocess(call_t *, ipc_data_t *);
 
 #endif