diff --git a/src/event.c b/src/event.c
index 312d9faf9..b33f0946f 100644
--- a/src/event.c
+++ b/src/event.c
@@ -8,6 +8,8 @@
 #include "thread.h"
 #include "event.h"
 
+static int event_log (const char *fmt, va_list ap, char *s, const size_t sz) __attribute__ ((format (printf, 1, 0)));
+
 void event_call (const u32 id, hashcat_ctx_t *hashcat_ctx, const void *buf, const size_t len)
 {
   event_ctx_t *event_ctx = hashcat_ctx->event_ctx;