1 files changed, 4 insertions, 0 deletions
diff --git a/src/user/lib/libc/include/string.h b/src/user/lib/libc/include/string.h
index 54fdf7a..5b86868 100644
--- a/src/user/lib/libc/include/string.h
+++ b/src/user/lib/libc/include/string.h
@@ -2,6 +2,7 @@
 #define DEF_LIB_STRING_H
 
 #include <types.h>
+#include <stdarg.h>
 
 #ifdef __cplusplus
 extern "C" { namespace libc {
@@ -20,6 +21,9 @@ int strcmp(const char *s1, const char *s2);
 
 char* format_int(char* buf, int number);
 char* format_hex(char *buf, unsigned v);
+int printf_str_len(const char *fmt, va_list arg);
+int vsprintf(char *buf, const char *fmt, va_list arg);
+int sprintf(char *buf, const char *fmt, ...);
 
 #ifdef __cplusplus
 } }