| Message ID | 31922e5e-3045-0a6f-e090-d78eb745efd0@vivanet.hu |
|---|---|
| State | New |
| Headers | show |
| Series | [FFmpeg-devel] avformat/hlsenc: compiler warning fix | expand |
| Context | Check | Description |
|---|---|---|
| andriy/ffmpeg-patchwork | success | Make fate finished |
On Mon, Jan 20, 2020 at 8:35 AM Bodecs Bela <bodecsb@vivanet.hu> wrote: > Dear All, > > This patch corrects compiler warning about returning possibly uninitialized > variable in hls_write_header function. > > Which compiler warns about this? Regarding the patch: It's probably better to explicitly return 0 at the end of hls_write_header() (as well as dash_write_header()). - Andreas
2020.01.20. 8:46 keltezéssel, Andreas Rheinhardt írta: > On Mon, Jan 20, 2020 at 8:35 AM Bodecs Bela <bodecsb@vivanet.hu> wrote: > >> Dear All, >> >> This patch corrects compiler warning about returning possibly uninitialized >> variable in hls_write_header function. >> >> Which compiler warns about this? libavformat/hlsenc.c: In function ‘hls_write_header’: libavformat/hlsenc.c:2174: warning: ‘ret’ may be used uninitialized in this function gcc version 4.4.7 20120313 (Red Hat 4.4.7-23) (GCC) > Regarding the patch: It's probably better to explicitly return 0 at the end > of hls_write_header() (as well as dash_write_header()). I have no objection, but maybe in a separate patch? > > - Andreas > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
Am Mo., 20. Jan. 2020 um 09:41 Uhr schrieb Bodecs Bela <bodecsb@vivanet.hu>: > > > 2020.01.20. 8:46 keltezéssel, Andreas Rheinhardt írta: > > On Mon, Jan 20, 2020 at 8:35 AM Bodecs Bela <bodecsb@vivanet.hu> wrote: > > > >> Dear All, > >> > >> This patch corrects compiler warning about returning possibly uninitialized > >> variable in hls_write_header function. > >> > >> Which compiler warns about this? > > libavformat/hlsenc.c: In function ‘hls_write_header’: > libavformat/hlsenc.c:2174: warning: ‘ret’ may be used uninitialized in > this function Looks like a false positive, does not warn with newer compilers. Carl Eugen
2020.01.20. 13:07 keltezéssel, Carl Eugen Hoyos írta: > Am Mo., 20. Jan. 2020 um 09:41 Uhr schrieb Bodecs Bela <bodecsb@vivanet.hu>: >> >> 2020.01.20. 8:46 keltezéssel, Andreas Rheinhardt írta: >>> On Mon, Jan 20, 2020 at 8:35 AM Bodecs Bela <bodecsb@vivanet.hu> wrote: >>> >>>> Dear All, >>>> >>>> This patch corrects compiler warning about returning possibly uninitialized >>>> variable in hls_write_header function. >>>> >>>> Which compiler warns about this? >> libavformat/hlsenc.c: In function ‘hls_write_header’: >> libavformat/hlsenc.c:2174: warning: ‘ret’ may be used uninitialized in >> this function > Looks like a false positive, does not warn with newer compilers. yes and no. no, because if hls->nb_varstreams == 0, then for loop body never executes and so ret does not get any value. yes, because there is no chance for hls->nb_varstreams to be zero. so, I think setting ret to 0 at its declaration does not do any problem and logically right. > > Carl Eugen > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
Am Mo., 20. Jan. 2020 um 13:18 Uhr schrieb Bodecs Bela <bodecsb@vivanet.hu>: > > > 2020.01.20. 13:07 keltezéssel, Carl Eugen Hoyos írta: > > Am Mo., 20. Jan. 2020 um 09:41 Uhr schrieb Bodecs Bela <bodecsb@vivanet.hu>: > >> > >> 2020.01.20. 8:46 keltezéssel, Andreas Rheinhardt írta: > >>> On Mon, Jan 20, 2020 at 8:35 AM Bodecs Bela <bodecsb@vivanet.hu> wrote: > >>> > >>>> Dear All, > >>>> > >>>> This patch corrects compiler warning about returning possibly uninitialized > >>>> variable in hls_write_header function. > >>>> > >>>> Which compiler warns about this? > >> libavformat/hlsenc.c: In function ‘hls_write_header’: > >> libavformat/hlsenc.c:2174: warning: ‘ret’ may be used uninitialized in > >> this function > > Looks like a false positive, does not warn with newer compilers. > > yes and no. > > no, because if hls->nb_varstreams == 0, then for loop body never > executes and so ret does not get any value. > > yes, because there is no chance for hls->nb_varstreams to be zero. > > so, I think setting ret to 0 at its declaration does not do any problem > and logically right. No, update your compiler instead. Carl Eugen
2020.01.20. 13:46 keltezéssel, Carl Eugen Hoyos írta: > Am Mo., 20. Jan. 2020 um 13:18 Uhr schrieb Bodecs Bela <bodecsb@vivanet.hu>: >> >> 2020.01.20. 13:07 keltezéssel, Carl Eugen Hoyos írta: >>> Am Mo., 20. Jan. 2020 um 09:41 Uhr schrieb Bodecs Bela <bodecsb@vivanet.hu>: >>>> 2020.01.20. 8:46 keltezéssel, Andreas Rheinhardt írta: >>>>> On Mon, Jan 20, 2020 at 8:35 AM Bodecs Bela <bodecsb@vivanet.hu> wrote: >>>>> >>>>>> Dear All, >>>>>> >>>>>> This patch corrects compiler warning about returning possibly uninitialized >>>>>> variable in hls_write_header function. >>>>>> >>>>>> Which compiler warns about this? >>>> libavformat/hlsenc.c: In function ‘hls_write_header’: >>>> libavformat/hlsenc.c:2174: warning: ‘ret’ may be used uninitialized in >>>> this function >>> Looks like a false positive, does not warn with newer compilers. >> yes and no. >> >> no, because if hls->nb_varstreams == 0, then for loop body never >> executes and so ret does not get any value. >> >> yes, because there is no chance for hls->nb_varstreams to be zero. >> >> so, I think setting ret to 0 at its declaration does not do any problem >> and logically right. > No, update your compiler instead. which of my statements did your "No" reference? > > Carl Eugen > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
Am Mo., 20. Jan. 2020 um 13:56 Uhr schrieb Bodecs Bela <bodecsb@vivanet.hu>: > > > 2020.01.20. 13:46 keltezéssel, Carl Eugen Hoyos írta: > > Am Mo., 20. Jan. 2020 um 13:18 Uhr schrieb Bodecs Bela <bodecsb@vivanet.hu>: > >> > >> 2020.01.20. 13:07 keltezéssel, Carl Eugen Hoyos írta: > >>> Am Mo., 20. Jan. 2020 um 09:41 Uhr schrieb Bodecs Bela <bodecsb@vivanet.hu>: > >>>> 2020.01.20. 8:46 keltezéssel, Andreas Rheinhardt írta: > >>>>> On Mon, Jan 20, 2020 at 8:35 AM Bodecs Bela <bodecsb@vivanet.hu> wrote: > >>>>> > >>>>>> Dear All, > >>>>>> > >>>>>> This patch corrects compiler warning about returning possibly uninitialized > >>>>>> variable in hls_write_header function. > >>>>>> > >>>>>> Which compiler warns about this? > >>>> libavformat/hlsenc.c: In function ‘hls_write_header’: > >>>> libavformat/hlsenc.c:2174: warning: ‘ret’ may be used uninitialized in > >>>> this function > >>> Looks like a false positive, does not warn with newer compilers. > >> yes and no. > >> > >> no, because if hls->nb_varstreams == 0, then for loop body never > >> executes and so ret does not get any value. > >> > >> yes, because there is no chance for hls->nb_varstreams to be zero. > >> > >> so, I think setting ret to 0 at its declaration does not do any problem > >> and logically right. > > No, update your compiler instead. > which of my statements did your "No" reference? Both. Please cut your quotes, Carl Eugen
2020.01.20. 14:02 keltezéssel, Carl Eugen Hoyos írta: > >>>>>>>> This patch corrects compiler warning about returning possibly uninitialized >>>>>>>> variable in hls_write_header function. >>>>>>>> >>>>>>>> Which compiler warns about this? >>>>>> libavformat/hlsenc.c: In function ‘hls_write_header’: >>>>>> libavformat/hlsenc.c:2174: warning: ‘ret’ may be used uninitialized in >>>>>> this function >>>>> Looks like a false positive, does not warn with newer compilers. >>>> yes and no. >>>> >>>> no, because if hls->nb_varstreams == 0, then for loop body never >>>> executes and so ret does not get any value. >>>> >>>> yes, because there is no chance for hls->nb_varstreams to be zero. >>>> >>>> so, I think setting ret to 0 at its declaration does not do any problem >>>> and logically right. >>> No, update your compiler instead. >> which of my statements did your "No" reference? > Both. Thank you for your help. Maybe due to my poor english, but I really do not see, I really did test with other compiler and really did not give warning any longer, but it does not help that the ret varaiable remain uninitalized but may be returned. As I know theoretically there is no default value of an int variable. So why the warning did disappear? > > Please cut your quotes, Carl Eugen ok > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
Am Mo., 20. Jan. 2020 um 14:18 Uhr schrieb Bodecs Bela <bodecsb@vivanet.hu>: > > > 2020.01.20. 14:02 keltezéssel, Carl Eugen Hoyos írta: > > > >>>>>>>> This patch corrects compiler warning about returning possibly uninitialized > >>>>>>>> variable in hls_write_header function. > >>>>>>>> > >>>>>>>> Which compiler warns about this? > >>>>>> libavformat/hlsenc.c: In function ‘hls_write_header’: > >>>>>> libavformat/hlsenc.c:2174: warning: ‘ret’ may be used uninitialized in > >>>>>> this function > >>>>> Looks like a false positive, does not warn with newer compilers. > >>>> yes and no. > >>>> > >>>> no, because if hls->nb_varstreams == 0, then for loop body never > >>>> executes and so ret does not get any value. > >>>> > >>>> yes, because there is no chance for hls->nb_varstreams to be zero. > >>>> > >>>> so, I think setting ret to 0 at its declaration does not do any problem > >>>> and logically right. > >>> No, update your compiler instead. > >> which of my statements did your "No" reference? > > Both. > > Thank you for your help. Maybe due to my poor english, but I really do > not see, > > I really did test with other compiler and really did not give warning > any longer, > > but it does not help that the ret varaiable remain uninitalized but may > be returned. > > As I know theoretically there is no default value of an int variable. > > So why the warning did disappear? I believe newer compilers detect that hls->nb_varstreams cannot be zero. Carl Eugen
2020.01.20. 14:25 keltezéssel, Carl Eugen Hoyos írta: > Am Mo., 20. Jan. 2020 um 14:18 Uhr schrieb Bodecs Bela <bodecsb@vivanet.hu>: >> >> 2020.01.20. 14:02 keltezéssel, Carl Eugen Hoyos írta: >>>>>>>>>> This patch corrects compiler warning about returning possibly uninitialized >>>>>>>>>> variable in hls_write_header function. >>>>>>>>>> >>>>>>>>>> Which compiler warns about this? >>>>>>>> libavformat/hlsenc.c: In function ‘hls_write_header’: >>>>>>>> libavformat/hlsenc.c:2174: warning: ‘ret’ may be used uninitialized in >>>>>>>> this function >>>>>>> Looks like a false positive, does not warn with newer compilers. >>>>>> yes and no. >>>>>> >>>>>> no, because if hls->nb_varstreams == 0, then for loop body never >>>>>> executes and so ret does not get any value. >>>>>> >>>>>> yes, because there is no chance for hls->nb_varstreams to be zero. >>>>>> >>>>>> so, I think setting ret to 0 at its declaration does not do any problem >>>>>> and logically right. >>>>> No, update your compiler instead. >>>> which of my statements did your "No" reference? >>> Both. >> Thank you for your help. Maybe due to my poor english, but I really do >> not see, >> >> I really did test with other compiler and really did not give warning >> any longer, >> >> but it does not help that the ret varaiable remain uninitalized but may >> be returned. >> >> As I know theoretically there is no default value of an int variable. >> >> So why the warning did disappear? > I believe newer compilers detect that hls->nb_varstreams cannot > be zero. ok > Carl Eugen > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
On Mon, Jan 20, 2020 at 2:26 PM Carl Eugen Hoyos <ceffmpeg@gmail.com> wrote: > Am Mo., 20. Jan. 2020 um 14:18 Uhr schrieb Bodecs Bela <bodecsb@vivanet.hu > >: > > 2020.01.20. 14:02 keltezéssel, Carl Eugen Hoyos írta: > > So why the warning did disappear? > > I believe newer compilers detect that hls->nb_varstreams cannot > be zero. > > I don't think so (a compiler has no way to find this out unless it is doing an LTO-build). It's probably that the warnings were overly aggressive and have been toned down. - Andreas
diff --git a/libavformat/hlsenc.c b/libavformat/hlsenc.c index d130f03ea62..1661f7aacba 100644 --- a/libavformat/hlsenc.c +++ b/libavformat/hlsenc.c @@ -2170,7 +2170,7 @@ fail: static int hls_write_header(AVFormatContext *s) { HLSContext *hls = s->priv_data; - int ret, i, j; + int ret = 0, i, j; VariantStream *vs = NULL; for (i = 0; i < hls->nb_varstreams; i++) {