Index: uspace/dist/src/c/demos/edit/edit.c
===================================================================
--- uspace/dist/src/c/demos/edit/edit.c	(revision cde999aca79219e8751af76502001a86d411d176)
+++ uspace/dist/src/c/demos/edit/edit.c	(revision 847844a5c1c6014e479cb00bf10c9d740927aa2d)
@@ -190,5 +190,5 @@
 	cons_event_t ev;
 	bool new_file;
-	int rc;
+	errno_t rc;
 
 	con = console_init(stdin, stdout);
@@ -580,5 +580,5 @@
 {
 	spt_t sp, ep;
-	int rc;
+	errno_t rc;
 
 	status_display("Saving...");
@@ -588,9 +588,9 @@
 	rc = file_save_range(fname, &sp, &ep);
 
-	switch (rc) {
-	case EINVAL:
+	switch ((case_errno_t) rc) {
+	case (case_errno_t) EINVAL:
 		status_display("Error opening file!");
 		break;
-	case EIO:
+	case (case_errno_t) EIO:
 		status_display("Error writing data!");
 		break;
@@ -615,5 +615,5 @@
 	}
 
-	int rc = file_save(fname);
+	errno_t rc = file_save(fname);
 	if (rc != EOK)
 		return;
@@ -1330,5 +1330,5 @@
 	
 	match_t match;
-	int rc = search_next_match(search, &match);
+	errno_t rc = search_next_match(search, &match);
 	if (rc != EOK) {
 		status_display("Failed searching.");
@@ -1448,5 +1448,5 @@
 	size_t off;
 	wchar_t c;
-	int rc;
+	errno_t rc;
 
 	rc = clipboard_get_str(&str);
Index: uspace/dist/src/c/demos/edit/search.c
===================================================================
--- uspace/dist/src/c/demos/edit/search.c	(revision cde999aca79219e8751af76502001a86d411d176)
+++ uspace/dist/src/c/demos/edit/search.c	(revision 847844a5c1c6014e479cb00bf10c9d740927aa2d)
@@ -104,10 +104,10 @@
 }
 
-int search_next_match(search_t *s, match_t *match)
+errno_t search_next_match(search_t *s, match_t *match)
 {
 	search_equals_fn eq = s->ops.equals;
 	
 	wchar_t cur_char;
-	int rc = EOK;
+	errno_t rc = EOK;
 	while ((rc = s->ops.producer(s->client_data, &cur_char)) == EOK && cur_char > 0) {
 		/* Deal with mismatches */
Index: uspace/dist/src/c/demos/edit/search.h
===================================================================
--- uspace/dist/src/c/demos/edit/search.h	(revision cde999aca79219e8751af76502001a86d411d176)
+++ uspace/dist/src/c/demos/edit/search.h	(revision 847844a5c1c6014e479cb00bf10c9d740927aa2d)
@@ -42,6 +42,6 @@
 typedef struct search search_t;
 typedef bool (*search_equals_fn)(const wchar_t, const wchar_t);
-typedef int (*search_producer_fn)(void *, wchar_t *);
-typedef int (*search_mark_fn)(void *, void **);
+typedef errno_t (*search_producer_fn)(void *, wchar_t *);
+typedef errno_t (*search_mark_fn)(void *, void **);
 typedef void (*search_mark_free_fn)(void *);
 
@@ -60,5 +60,5 @@
 extern bool char_exact_equals(const wchar_t, const wchar_t);
 extern search_t *search_init(const char *, void *, search_ops_t, bool);
-extern int search_next_match(search_t *, match_t *);
+extern errno_t search_next_match(search_t *, match_t *);
 extern void search_fini(search_t *);
 
Index: uspace/dist/src/c/demos/edit/sheet.c
===================================================================
--- uspace/dist/src/c/demos/edit/sheet.c	(revision cde999aca79219e8751af76502001a86d411d176)
+++ uspace/dist/src/c/demos/edit/sheet.c	(revision 847844a5c1c6014e479cb00bf10c9d740927aa2d)
@@ -67,5 +67,5 @@
 
 /** Initialize an empty sheet. */
-int sheet_create(sheet_t **rsh)
+errno_t sheet_create(sheet_t **rsh)
 {
 	sheet_t *sh;
@@ -101,5 +101,5 @@
  *		and vice versa.
  */
-int sheet_insert(sheet_t *sh, spt_t *pos, enum dir_spec dir, char *str)
+errno_t sheet_insert(sheet_t *sh, spt_t *pos, enum dir_spec dir, char *str)
 {
 	char *ipp;
@@ -147,5 +147,5 @@
  * @return	EOK on success or an error code.
  **/
-int sheet_delete(sheet_t *sh, spt_t *spos, spt_t *epos)
+errno_t sheet_delete(sheet_t *sh, spt_t *spos, spt_t *epos)
 {
 	char *spp;
Index: uspace/dist/src/c/demos/edit/sheet.h
===================================================================
--- uspace/dist/src/c/demos/edit/sheet.h	(revision cde999aca79219e8751af76502001a86d411d176)
+++ uspace/dist/src/c/demos/edit/sheet.h	(revision 847844a5c1c6014e479cb00bf10c9d740927aa2d)
@@ -90,7 +90,7 @@
 } tag_t;
 
-extern int sheet_create(sheet_t **);
-extern int sheet_insert(sheet_t *, spt_t *, enum dir_spec, char *);
-extern int sheet_delete(sheet_t *, spt_t *, spt_t *);
+extern errno_t sheet_create(sheet_t **);
+extern errno_t sheet_insert(sheet_t *, spt_t *, enum dir_spec, char *);
+extern errno_t sheet_delete(sheet_t *, spt_t *, spt_t *);
 extern void sheet_copy_out(sheet_t *, spt_t const *, spt_t const *, char *,
     size_t, spt_t *);
Index: uspace/dist/src/c/demos/hello/hello.c
===================================================================
--- uspace/dist/src/c/demos/hello/hello.c	(revision cde999aca79219e8751af76502001a86d411d176)
+++ uspace/dist/src/c/demos/hello/hello.c	(revision 847844a5c1c6014e479cb00bf10c9d740927aa2d)
@@ -1,3 +1,3 @@
-extern int putchar(char);
+extern errno_t putchar(char);
 
 #define TERMINATOR '!'
Index: uspace/dist/src/c/demos/tetris/scores.c
===================================================================
--- uspace/dist/src/c/demos/tetris/scores.c	(revision cde999aca79219e8751af76502001a86d411d176)
+++ uspace/dist/src/c/demos/tetris/scores.c	(revision 847844a5c1c6014e479cb00bf10c9d740927aa2d)
@@ -206,9 +206,9 @@
 }
 
-int loadscores(void)
+errno_t loadscores(void)
 {
 	FILE *f;
 	size_t cnt;
-	int rc;
+	errno_t rc;
 
 	f = fopen("/data/tetris.sco", "rb");
@@ -229,5 +229,5 @@
 	FILE *f;
 	size_t cnt;
-	int rc;
+	errno_t rc;
 
 	f = fopen("/data/tetris.sco", "wb");
Index: uspace/dist/src/c/demos/tetris/scores.h
===================================================================
--- uspace/dist/src/c/demos/tetris/scores.h	(revision cde999aca79219e8751af76502001a86d411d176)
+++ uspace/dist/src/c/demos/tetris/scores.h	(revision 847844a5c1c6014e479cb00bf10c9d740927aa2d)
@@ -72,5 +72,5 @@
 extern void initscores(void);
 extern void insertscore(int score, int level);
-extern int loadscores(void);
+extern errno_t loadscores(void);
 extern void savescores(void);
 
Index: uspace/dist/src/c/demos/tetris/screen.c
===================================================================
--- uspace/dist/src/c/demos/tetris/screen.c	(revision cde999aca79219e8751af76502001a86d411d176)
+++ uspace/dist/src/c/demos/tetris/screen.c	(revision 847844a5c1c6014e479cb00bf10c9d740927aa2d)
@@ -147,5 +147,5 @@
 {
 	sysarg_t ccap;
-	int rc = console_get_color_cap(console, &ccap);
+	errno_t rc = console_get_color_cap(console, &ccap);
 	
 	if (rc != 0)
@@ -353,5 +353,5 @@
  *
  */
-int tgetchar(void)
+errno_t tgetchar(void)
 {
 	/*
@@ -392,5 +392,5 @@
  *
  */
-int twait(void)
+errno_t twait(void)
 {
 	wchar_t c = 0;
Index: uspace/dist/src/c/demos/tetris/screen.h
===================================================================
--- uspace/dist/src/c/demos/tetris/screen.h	(revision cde999aca79219e8751af76502001a86d411d176)
+++ uspace/dist/src/c/demos/tetris/screen.h	(revision 847844a5c1c6014e479cb00bf10c9d740927aa2d)
@@ -71,5 +71,5 @@
 extern void clear_screen(void);
 
-extern int put(int);
+extern errno_t put(int);
 extern void scr_clear(void);
 extern void scr_end(void);
@@ -80,6 +80,6 @@
 
 extern void tsleep(void);
-extern int tgetchar(void);
-extern int twait(void);
+extern errno_t tgetchar(void);
+extern errno_t twait(void);
 
 /** @}
Index: uspace/dist/src/c/demos/tetris/shapes.c
===================================================================
--- uspace/dist/src/c/demos/tetris/shapes.c	(revision cde999aca79219e8751af76502001a86d411d176)
+++ uspace/dist/src/c/demos/tetris/shapes.c	(revision 847844a5c1c6014e479cb00bf10c9d740927aa2d)
@@ -93,5 +93,5 @@
  * taking the current board into account.
  */
-int fits_in(const struct shape *shape, int pos)
+errno_t fits_in(const struct shape *shape, int pos)
 {
 	const int *o = shape->off;
Index: uspace/dist/src/c/demos/tetris/tetris.h
===================================================================
--- uspace/dist/src/c/demos/tetris/tetris.h	(revision cde999aca79219e8751af76502001a86d411d176)
+++ uspace/dist/src/c/demos/tetris/tetris.h	(revision 847844a5c1c6014e479cb00bf10c9d740927aa2d)
@@ -194,5 +194,5 @@
 extern int classic;
 
-extern int fits_in(const struct shape *, int);
+extern errno_t fits_in(const struct shape *, int);
 extern void place(const struct shape *, int, int);
 extern void stop(const char *);
Index: uspace/dist/src/c/demos/top/screen.c
===================================================================
--- uspace/dist/src/c/demos/top/screen.c	(revision cde999aca79219e8751af76502001a86d411d176)
+++ uspace/dist/src/c/demos/top/screen.c	(revision 847844a5c1c6014e479cb00bf10c9d740927aa2d)
@@ -537,5 +537,5 @@
  *
  */
-int tgetchar(unsigned int sec)
+errno_t tgetchar(unsigned int sec)
 {
 	/*
Index: uspace/dist/src/c/demos/top/screen.h
===================================================================
--- uspace/dist/src/c/demos/top/screen.h	(revision cde999aca79219e8751af76502001a86d411d176)
+++ uspace/dist/src/c/demos/top/screen.h	(revision 847844a5c1c6014e479cb00bf10c9d740927aa2d)
@@ -47,5 +47,5 @@
     PRINTF_ATTRIBUTE(1, 2);
 
-extern int tgetchar(unsigned int);
+extern errno_t tgetchar(unsigned int);
 
 #endif