1 files changed, 1 insertions, 1 deletions
diff --git a/README.md b/README.md
index 5ee138e..8420a5b 100644
--- a/README.md
+++ b/README.md
@@ -52,7 +52,7 @@ int snprintf(char* buffer, size_t count, const char* format, ...);
 int vsnprintf(char* buffer, size_t count, const char* format, va_list va);
 
 // call output function (instead of buffer)
-int fctprintf(void (*out)(char character), const char* format, ...);
+int fctprintf(void (*out)(char character, void* user), void* user, const char* format, ...);
 ```