[FFmpeg-devel] [PATCH] ffmpeg: check return value of avio_closep for progress report

[Ganesh Ajjanagadde]

avio_closep is not guaranteed to succeed, and its return value can
contain information regarding failure of preceding writes and silent
loss of data (man 2 close, man fclose). Users should know when the
progress was not successfully logged, and so a diagnostic is printed
here.

The reason only one of these is changed in the patch is to get feedback:
a quick glance shows a large number of unchecked avio_close operations.
It may be tedious to check all of them, and relative importance varies
across instances. This was one which I feel is important.

Signed-off-by: Ganesh Ajjanagadde <gajjanagadde at gmail.com>
---
 ffmpeg.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/ffmpeg.c b/ffmpeg.c
index ee72f91..81f3697 100644
--- a/ffmpeg.c
+++ b/ffmpeg.c
@@ -1512,6 +1512,7 @@ static void print_report(int is_last_report, int64_t timer_start, int64_t cur_ti
     static int64_t last_time = -1;
     static int qp_histogram[52];
     int hours, mins, secs, us;
+    int ret;
     float t;
 
     if (!print_stats && !is_last_report && !progress_avio)
@@ -1678,7 +1679,9 @@ static void print_report(int is_last_report, int64_t timer_start, int64_t cur_ti
         avio_flush(progress_avio);
         av_bprint_finalize(&buf_script, NULL);
         if (is_last_report) {
-            avio_closep(&progress_avio);
+            if ((ret = avio_closep(&progress_avio)) < 0)
+                av_log(NULL, AV_LOG_ERROR,
+                       "not possible to close progress log, loss of information possible: %s\n", av_err2str(ret));
         }
     }
 
-- 
2.6.4