diff --git a/include/proto/htx.h b/include/proto/htx.h
index 91a2086a3..dd525fed3 100644
--- a/include/proto/htx.h
+++ b/include/proto/htx.h
@@ -443,7 +443,7 @@ static inline void htx_dump(struct htx *htx)
         fprintf(stderr, "htx:%p [ size=%u - data=%u - used=%u - wrap=%s - extra=%lu]\n",
                 htx, htx->size, htx->data, htx->used,
                 (!htx->used || htx->tail+1 == htx->wrap) ? "NO" : "YES",
-		htx->extra);
+		(unsigned long)htx->extra);
         fprintf(stderr, "\thead=%d - tail=%u - front=%u - wrap=%u\n",
                 htx_get_head(htx), htx->tail, htx->front, htx->wrap);