Index: uspace/lib/c/include/device/clock_dev.h
===================================================================
--- uspace/lib/c/include/device/clock_dev.h	(revision c19a5a59bb6be5cf8da4e0c9a6a35d207103bc14)
+++ uspace/lib/c/include/device/clock_dev.h	(revision e211ea04fccf33d4cb2092f630a29e893e096a02)
@@ -44,6 +44,6 @@
 } clock_dev_method_t;
 
-extern int clock_dev_time_get(async_sess_t *, struct tm *);
-extern int clock_dev_time_set(async_sess_t *, struct tm *);
+extern errno_t clock_dev_time_get(async_sess_t *, struct tm *);
+extern errno_t clock_dev_time_set(async_sess_t *, struct tm *);
 
 #endif
Index: uspace/lib/c/include/device/hw_res.h
===================================================================
--- uspace/lib/c/include/device/hw_res.h	(revision c19a5a59bb6be5cf8da4e0c9a6a35d207103bc14)
+++ uspace/lib/c/include/device/hw_res.h	(revision e211ea04fccf33d4cb2092f630a29e893e096a02)
@@ -116,12 +116,12 @@
 }
 
-extern int hw_res_get_resource_list(async_sess_t *, hw_resource_list_t *);
-extern int hw_res_enable_interrupt(async_sess_t *, int);
-extern int hw_res_disable_interrupt(async_sess_t *, int);
-extern int hw_res_clear_interrupt(async_sess_t *, int);
+extern errno_t hw_res_get_resource_list(async_sess_t *, hw_resource_list_t *);
+extern errno_t hw_res_enable_interrupt(async_sess_t *, int);
+extern errno_t hw_res_disable_interrupt(async_sess_t *, int);
+extern errno_t hw_res_clear_interrupt(async_sess_t *, int);
 
-extern int hw_res_dma_channel_setup(async_sess_t *, unsigned int, uint32_t,
+extern errno_t hw_res_dma_channel_setup(async_sess_t *, unsigned int, uint32_t,
     uint32_t, uint8_t);
-extern int hw_res_dma_channel_remain(async_sess_t *, unsigned, size_t *);
+extern errno_t hw_res_dma_channel_remain(async_sess_t *, unsigned, size_t *);
 
 #endif
Index: uspace/lib/c/include/device/hw_res_parsed.h
===================================================================
--- uspace/lib/c/include/device/hw_res_parsed.h	(revision c19a5a59bb6be5cf8da4e0c9a6a35d207103bc14)
+++ uspace/lib/c/include/device/hw_res_parsed.h	(revision e211ea04fccf33d4cb2092f630a29e893e096a02)
@@ -154,7 +154,7 @@
 }
 
-extern int hw_res_list_parse(const pio_window_t *, const hw_resource_list_t *,
+extern errno_t hw_res_list_parse(const pio_window_t *, const hw_resource_list_t *,
     hw_res_list_parsed_t *, int);
-extern int hw_res_get_list_parsed(async_sess_t *, hw_res_list_parsed_t *, int);
+extern errno_t hw_res_get_list_parsed(async_sess_t *, hw_res_list_parsed_t *, int);
 
 #endif
Index: uspace/lib/c/include/device/led_dev.h
===================================================================
--- uspace/lib/c/include/device/led_dev.h	(revision c19a5a59bb6be5cf8da4e0c9a6a35d207103bc14)
+++ uspace/lib/c/include/device/led_dev.h	(revision e211ea04fccf33d4cb2092f630a29e893e096a02)
@@ -43,5 +43,5 @@
 } led_dev_method_t;
 
-extern int led_dev_color_set(async_sess_t *, pixel_t);
+extern errno_t led_dev_color_set(async_sess_t *, pixel_t);
 
 #endif
Index: uspace/lib/c/include/device/pio_window.h
===================================================================
--- uspace/lib/c/include/device/pio_window.h	(revision c19a5a59bb6be5cf8da4e0c9a6a35d207103bc14)
+++ uspace/lib/c/include/device/pio_window.h	(revision e211ea04fccf33d4cb2092f630a29e893e096a02)
@@ -51,5 +51,5 @@
 } pio_window_t;
 
-extern int pio_window_get(async_sess_t *, pio_window_t *);
+extern errno_t pio_window_get(async_sess_t *, pio_window_t *);
 
 #endif