On Fri, May 05, 2017 at 09:44:46AM +0200, Carl Eugen Hoyos wrote: > 2017-05-05 9:42 GMT+02:00 Aaron Levinson <alevi...@aracnet.com>: > > On 5/5/2017 12:20 AM, Carl Eugen Hoyos wrote: > >> > >> 2017-05-05 3:29 GMT+02:00 Aaron Levinson <alevi...@aracnet.com>: > >>> > >>> On 5/4/2017 4:27 PM, Carl Eugen Hoyos wrote: > >>>> > >>>> > >>>> Hi! > >>>> > >>>> Attached patch is one possibility to fix the following warning with gcc > >>>> 7: > >>>> libavutil/timecode.c: In function ‘av_timecode_make_string’: > >>>> libavutil/timecode.c:103:60: warning: ‘%02d’ directive output may be > >>>> truncated > >>>> writing between 2 and 10 bytes into a region of size between 0 and 7 > >>>> [-Wformat-truncation=] > >>>> snprintf(buf, AV_TIMECODE_STR_SIZE, "%s%02d:%02d:%02d%c%02d", > >>>> ^~~~ > >>>> libavutil/timecode.c:103:41: note: directive argument in the range [0, > >>>> 2147483647] > >>>> snprintf(buf, AV_TIMECODE_STR_SIZE, "%s%02d:%02d:%02d%c%02d", > >>>> ^~~~~~~~~~~~~~~~~~~~~~~~ > >>>> libavutil/timecode.c:103:5: note: ‘snprintf’ output between 12 and 32 > >>>> bytes > >>>> into a destination of size 16 > >>>> snprintf(buf, AV_TIMECODE_STR_SIZE, "%s%02d:%02d:%02d%c%02d", > >>>> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > >>>> neg ? "-" : "", > >>>> ~~~~~~~~~~~~~~~ > >>>> hh, mm, ss, drop ? ';' : ':', ff); > >>>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > >>>> > >>>> Several similar warnings are printed, an alternative is to disable the > >>>> warning. > >>>> > >>>> The warning seemed wrong on first sight but may actually be correct, we > >>>> accept invalid fps for timecode. > >>> > >>> > >>> > >>> Regarding the change in your patch: > >>> > >>> -#define AV_TIMECODE_STR_SIZE 16 > >>> +#define AV_TIMECODE_STR_SIZE 23 > >>> > >>> It seems like 23 characters wouldn't be sufficient based on the warning: > >>> "output between 12 and 32 bytes into a destination of size 16". I would > >>> guess that you would need at least 32 characters and perhaps one more (?) > >>> for the terminating null character to avoid that warning. > >> > >> > >> How can I reproduce / test your findings? > > > > > > #define AV_TIMECODE_STR_SIZE 32 or 33 and confirm that gcc 7 > > warnings go away. > > Of course! > Since the warnings go away with 23, they also go away with 32. > I just wonder why 23 isn't enough in your opinion? >
Because GCC says "‘snprintf’ output between 12 and 32 bytes". 32 bytes is fine with me, feel free to push with that value. -- Clément B.
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