Index: uspace/app/tester/stdio/stdio1.c
===================================================================
--- uspace/app/tester/stdio/stdio1.c	(revision 582a0b84b0a73672531e7b404a89997af41ba0b9)
+++ uspace/app/tester/stdio/stdio1.c	(revision 6fb8b2c38282012b1154d0e8fa18bbd84a81caec)
@@ -30,4 +30,5 @@
 #include <stdlib.h>
 #include <stddef.h>
+#include <str_error.h>
 #include <errno.h>
 #include "../tester.h"
@@ -46,5 +47,5 @@
 	file = fopen(file_name, "rt");
 	if (file == NULL) {
-		TPRINTF("errno = %d\n", errno);
+		TPRINTF("errno = %s\n", str_error_name(errno));
 		return "Failed opening file";
 	} else
@@ -54,5 +55,5 @@
 	size_t cnt = fread(buf, 1, BUF_SIZE, file);
 	if (ferror(file)) {
-		TPRINTF("errno = %d\n", errno);
+		TPRINTF("errno = %s\n", str_error_name(errno));
 		fclose(file);
 		return "Failed reading file";
@@ -65,5 +66,5 @@
 	TPRINTF("Seek to beginning...");
 	if (fseek(file, 0, SEEK_SET) != 0) {
-		TPRINTF("errno = %d\n", errno);
+		TPRINTF("errno = %s\n", str_error_name(errno));
 		fclose(file);
 		return "Failed seeking in file";
@@ -83,5 +84,5 @@
 	TPRINTF("Close...");
 	if (fclose(file) != 0) {
-		TPRINTF("errno = %d\n", errno);
+		TPRINTF("errno = %s\n", str_error_name(errno));
 		return "Failed closing file";
 	} else
Index: uspace/app/tester/stdio/stdio2.c
===================================================================
--- uspace/app/tester/stdio/stdio2.c	(revision 582a0b84b0a73672531e7b404a89997af41ba0b9)
+++ uspace/app/tester/stdio/stdio2.c	(revision 6fb8b2c38282012b1154d0e8fa18bbd84a81caec)
@@ -30,4 +30,5 @@
 #include <stdlib.h>
 #include <stddef.h>
+#include <str_error.h>
 #include <errno.h>
 #include "../tester.h"
@@ -42,5 +43,5 @@
 	file = fopen(file_name, "wt");
 	if (file == NULL) {
-		TPRINTF("errno = %d\n", errno);
+		TPRINTF("errno = %s\n", str_error_name(errno));
 		return "Failed opening file";
 	} else
@@ -53,5 +54,5 @@
 	TPRINTF("Close...");
 	if (fclose(file) != 0) {
-		TPRINTF("errno = %d\n", errno);
+		TPRINTF("errno = %s\n", str_error_name(errno));
 		return "Failed closing file";
 	} else
@@ -61,5 +62,5 @@
 	file = fopen(file_name, "rt");
 	if (file == NULL) {
-		TPRINTF("errno = %d\n", errno);
+		TPRINTF("errno = %s\n", str_error_name(errno));
 		return "Failed opening file";
 	} else
@@ -76,5 +77,5 @@
 	TPRINTF("\nClose...");
 	if (fclose(file) != 0) {
-		TPRINTF("errno = %d\n", errno);
+		TPRINTF("errno = %s\n", str_error_name(errno));
 		return "Failed closing file";
 	} else