fix(printf): use C conform `NULL` instead of C++ `nullptr`

Fixes #14

1 files changed, 1 insertions, 1 deletions

diff --git a/printf.c b/printf.c
index 8fe7048..56f60d6 100644
--- a/printf.c
+++ b/printf.c
@@ -647,7 +647,7 @@ int printf(const char* format, ...)
 {

   va_list va;

   va_start(va, format);

-  const int ret = _vsnprintf(_out_char, nullptr, (size_t)-1, format, va);

+  const int ret = _vsnprintf(_out_char, NULL, (size_t)-1, format, va);

   va_end(va);

   return ret;

 }