From: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Date: Tue, 13 Dec 2016 17:17:10 +0000 (-0500)
Subject: Fix: perform an explicit stdout flush in live even on empty packets
X-Git-Tag: v1.4.2~1
X-Git-Url: http://git.efficios.com/?p=babeltrace.git;a=commitdiff_plain;h=8dcb4e83662ffac2b204f9bfcc28bbd914edf390

Fix: perform an explicit stdout flush in live even on empty packets

This ensures that babeltrace makes the content of live buffers
visible even if the data packets received are empty.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
---

diff --git a/formats/lttng-live/lttng-live-comm.c b/formats/lttng-live/lttng-live-comm.c
index 7b4711be..6b65512c 100644
--- a/formats/lttng-live/lttng-live-comm.c
+++ b/formats/lttng-live/lttng-live-comm.c
@@ -650,17 +650,6 @@ retry:
 		goto end;
 	}
 
-	/*
-	 * Flush the output between attempts to grab a packet, thus
-	 * ensuring we flush at least at the periodical timer period.
-	 * This ensures the output remains reactive for interactive users and
-	 * that the output is flushed when redirected to a file by the shell.
-	 */
-	if (fflush(LTTNG_LIVE_OUTPUT_FP) < 0) {
-		perror("fflush");
-		goto error;
-	}
-
 	cmd.cmd = htobe32(LTTNG_VIEWER_GET_PACKET);
 	cmd.data_size = htobe64((uint64_t) sizeof(rq));
 	cmd.cmd_version = htobe32(0);
@@ -1293,6 +1282,17 @@ retry:
 				cur_index->ts_real.timestamp_begin;
 	}
 
+	/*
+	 * Flush the output between attempts to grab a packet, thus
+	 * ensuring we flush at least at the periodical timer period.
+	 * This ensures the output remains reactive for interactive users and
+	 * that the output is flushed when redirected to a file by the shell.
+	 */
+	if (fflush(LTTNG_LIVE_OUTPUT_FP) < 0) {
+		perror("fflush");
+		goto end;
+	}
+
 	if (pos->packet_size == 0 || pos->offset == EOF) {
 		goto end;
 	}