Index: libc/generic/io/printf.c
===================================================================
--- libc/generic/io/printf.c	(revision d1c4b9ebb506eb6fd936447df810dc5b7282680f)
+++ libc/generic/io/printf.c	(revision 80076f6b5d7b696fdf0e7302904edeb79f45b50a)
@@ -31,4 +31,8 @@
 #include <stdio.h>
 
+/** Print formatted text.
+ * @param fmt	format string
+ * \see For more details about format string see printf_core.
+ */
 int printf(const char *fmt, ...)
 {
Index: libc/generic/io/snprintf.c
===================================================================
--- libc/generic/io/snprintf.c	(revision d1c4b9ebb506eb6fd936447df810dc5b7282680f)
+++ libc/generic/io/snprintf.c	(revision 80076f6b5d7b696fdf0e7302904edeb79f45b50a)
@@ -31,4 +31,10 @@
 #include <io/printf_core.h>
 
+/** Print formatted to the given buffer with limited size.
+ * @param str	buffer
+ * @param size	buffer size
+ * @param fmt	format string
+ * \see For more details about format string see printf_core.
+ */
 int snprintf(char *str, size_t size, const char *fmt, ...)
 {
Index: libc/generic/io/sprintf.c
===================================================================
--- libc/generic/io/sprintf.c	(revision d1c4b9ebb506eb6fd936447df810dc5b7282680f)
+++ libc/generic/io/sprintf.c	(revision 80076f6b5d7b696fdf0e7302904edeb79f45b50a)
@@ -31,4 +31,9 @@
 #include <io/printf_core.h>
 
+/** Print formatted to the given buffer.
+ * @param str	buffer
+ * @param fmt	format string
+ * \see For more details about format string see printf_core.
+ */
 int sprintf(char *str, const char *fmt, ...)
 {
Index: libc/generic/io/vprintf.c
===================================================================
--- libc/generic/io/vprintf.c	(revision d1c4b9ebb506eb6fd936447df810dc5b7282680f)
+++ libc/generic/io/vprintf.c	(revision 80076f6b5d7b696fdf0e7302904edeb79f45b50a)
@@ -39,4 +39,9 @@
 }
 
+/** Print formatted text.
+ * @param fmt	format string
+ * @param ap	format parameters
+ * \see For more details about format string see printf_core.
+ */
 int vprintf(const char *fmt, va_list ap)
 {
Index: libc/generic/io/vsnprintf.c
===================================================================
--- libc/generic/io/vsnprintf.c	(revision d1c4b9ebb506eb6fd936447df810dc5b7282680f)
+++ libc/generic/io/vsnprintf.c	(revision 80076f6b5d7b696fdf0e7302904edeb79f45b50a)
@@ -84,4 +84,10 @@
 }
 
+/** Print formatted to the given buffer with limited size.
+ * @param str	buffer
+ * @param size	buffer size
+ * @param fmt	format string
+ * \see For more details about format string see printf_core.
+ */
 int vsnprintf(char *str, size_t size, const char *fmt, va_list ap)
 {
Index: libc/generic/io/vsprintf.c
===================================================================
--- libc/generic/io/vsprintf.c	(revision d1c4b9ebb506eb6fd936447df810dc5b7282680f)
+++ libc/generic/io/vsprintf.c	(revision 80076f6b5d7b696fdf0e7302904edeb79f45b50a)
@@ -31,4 +31,10 @@
 #include <io/printf_core.h>
 
+/** Print formatted to the given buffer.
+ * @param str	buffer
+ * @param fmt	format string
+ * @param ap	argument list
+ * \see For more details about format string see printf_core.
+ */
 int vsprintf(char *str, const char *fmt, va_list ap)
 {