From 2f9b125c1c6d617a34b8b9e726e1eea56d200cc1 Mon Sep 17 00:00:00 2001
From: ZYP <zzz858aaa@gmail.com>
Date: Sat, 12 Sep 2026 23:49:24 +0800
Subject: [PATCH] Flush Done lines when stdout is a pipe

setvbuf(stdout, NULL, _IOLBF, 0) so interactive completion messages
like "Done -> ..." reach piped clients immediately (antirez/h3.c#25).
---
 main.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/main.c b/main.c
index 7f11e470..e5b1de52 100644
--- a/main.c
+++ b/main.c
@@ -229,6 +229,10 @@ static int cli_frame(const h3_frame *frame, void *opaque) {
 }
 
 int main(int argc, char **argv) {
+    /* Line-buffer stdout so Done/status lines flush immediately when
+     * stdout is a pipe (non-TTY). See antirez/h3.c#25. */
+    setvbuf(stdout, NULL, _IOLBF, 0);
+
     enum { OPT_WIDTH = 1000, OPT_HEIGHT, OPT_RENDER_WIDTH, OPT_RENDER_HEIGHT,
            OPT_FRAMES, OPT_SECONDS, OPT_STEPS, OPT_REUSE,
            OPT_LAYERS,