Index: kernel/generic/src/printf/vsnprintf.c
===================================================================
--- kernel/generic/src/printf/vsnprintf.c	(revision 1b0b48e09eab2e821aca4d6f6b078ce38136134f)
+++ kernel/generic/src/printf/vsnprintf.c	(revision 58d5a7e7f52a72c963da8a40b5a38494bd631044)
@@ -37,4 +37,5 @@
 #include <string.h>
 #include <memstr.h>
+#include <errno.h>
 
 typedef struct {
@@ -87,5 +88,5 @@
 			wchar_t uc = chr_decode(str, &index, size);
 
-			if (!chr_encode(uc, data->dst, &data->len, data->size - 1))
+			if (chr_encode(uc, data->dst, &data->len, data->size - 1) != EOK)
 				break;
 		}
@@ -147,5 +148,5 @@
 		}
 		
-		if (!chr_encode(str[index], data->dst, &data->len, data->size - 1))
+		if (chr_encode(str[index], data->dst, &data->len, data->size - 1) != EOK)
 			break;