1 files changed, 2 insertions, 1 deletions
diff --git a/printf.c b/printf.c
index 56f60d6..f1a51e2 100644
--- a/printf.c
+++ b/printf.c
@@ -647,7 +647,8 @@ int printf(const char* format, ...)
 {
   va_list va;
   va_start(va, format);
-  const int ret = _vsnprintf(_out_char, NULL, (size_t)-1, format, va);
+  char buffer[1];
+  const int ret = _vsnprintf(_out_char, buffer, (size_t)-1, format, va);
   va_end(va);
   return ret;
 }