1 files changed, 2 insertions, 0 deletions
diff --git a/src/buffer.hpp b/src/buffer.hpp
index f9b2497548..3670332038 100644
--- a/src/buffer.hpp
+++ b/src/buffer.hpp
@@ -13,6 +13,7 @@
 #include <assert.h>
 #include <stdint.h>
 #include <ctype.h>
+#include <stdarg.h>
 
 #define BUF_INIT {{0}}
 
@@ -24,6 +25,7 @@ struct Buf {
 
 Buf *buf_sprintf(const char *format, ...)
     __attribute__ ((format (printf, 1, 2)));
+Buf *buf_vprintf(const char *format, va_list ap);
 
 static inline int buf_len(Buf *buf) {
     assert(buf->list.length);