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 cd146d764886d21032dbe4e0dfe8e0e01fc7c385..0a895b38622b9ddb6cd7554cdaa0c6e30ac30dad 100644 (file)
--- 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;
        }