Index: kernel/generic/include/udebug/udebug.h
===================================================================
--- kernel/generic/include/udebug/udebug.h	(revision b2a1fd92811bab5d05b74e0c829a43f348315cbc)
+++ kernel/generic/include/udebug/udebug.h	(revision e211ea04fccf33d4cb2092f630a29e893e096a02)
@@ -102,5 +102,5 @@
 void udebug_before_thread_runs(void);
 
-int udebug_task_cleanup(struct task *);
+errno_t udebug_task_cleanup(struct task *);
 void udebug_thread_fault(void);
 
Index: kernel/generic/include/udebug/udebug_ipc.h
===================================================================
--- kernel/generic/include/udebug/udebug_ipc.h	(revision b2a1fd92811bab5d05b74e0c829a43f348315cbc)
+++ kernel/generic/include/udebug/udebug_ipc.h	(revision e211ea04fccf33d4cb2092f630a29e893e096a02)
@@ -38,5 +38,5 @@
 #include <ipc/ipc.h>
 
-int udebug_request_preprocess(call_t *call, phone_t *phone);
+errno_t udebug_request_preprocess(call_t *call, phone_t *phone);
 void udebug_call_receive(call_t *call);
 
Index: kernel/generic/include/udebug/udebug_ops.h
===================================================================
--- kernel/generic/include/udebug/udebug_ops.h	(revision b2a1fd92811bab5d05b74e0c829a43f348315cbc)
+++ kernel/generic/include/udebug/udebug_ops.h	(revision e211ea04fccf33d4cb2092f630a29e893e096a02)
@@ -41,19 +41,19 @@
 #include <stddef.h>
 
-int udebug_begin(call_t *call, bool *active);
-int udebug_end(void);
-int udebug_set_evmask(udebug_evmask_t mask);
+errno_t udebug_begin(call_t *call, bool *active);
+errno_t udebug_end(void);
+errno_t udebug_set_evmask(udebug_evmask_t mask);
 
-int udebug_go(thread_t *t, call_t *call);
-int udebug_stop(thread_t *t, call_t *call);
+errno_t udebug_go(thread_t *t, call_t *call);
+errno_t udebug_stop(thread_t *t, call_t *call);
 
-int udebug_thread_read(void **buffer, size_t buf_size, size_t *stored,
+errno_t udebug_thread_read(void **buffer, size_t buf_size, size_t *stored,
     size_t *needed);
-int udebug_name_read(char **data, size_t *data_size);
-int udebug_args_read(thread_t *t, void **buffer);
+errno_t udebug_name_read(char **data, size_t *data_size);
+errno_t udebug_args_read(thread_t *t, void **buffer);
 
-int udebug_regs_read(thread_t *t, void **buffer);
+errno_t udebug_regs_read(thread_t *t, void **buffer);
 
-int udebug_mem_read(sysarg_t uspace_addr, size_t n, void **buffer);
+errno_t udebug_mem_read(sysarg_t uspace_addr, size_t n, void **buffer);
 
 #endif