[FFmpeg-devel] [PATCH]lavc/avpacket: Make pkt parameter of av_packet_get_side_data() const

[Carl Eugen Hoyos]

2017-02-26 11:51 GMT+01:00 Nicolas George <george at nsup.org>:
> L'octidi 8 ventôse, an CCXXV, Carl Eugen Hoyos a écrit :
>> Hi!
>>
>> I believe adding const to the declaration of av_packet_get_side_data()
>> better reflects its intention, also fixes a warning.
>>
>> Please comment, Carl Eugen
>
>> From a17c4bab8cd21c15e91f5efd03d5900eda29090b Mon Sep 17 00:00:00 2001
>> From: Carl Eugen Hoyos <cehoyos at ag.or.at>
>> Date: Sun, 26 Feb 2017 11:39:07 +0100
>> Subject: [PATCH] lavc/avpacket: Make pkt parameter of
>>  av_packet_get_side_data() const.
>> MIME-Version: 1.0
>> Content-Type: text/plain; charset=UTF-8
>> Content-Transfer-Encoding: 8bit
>>
>> Reflects the actual code and silences a gcc warning:
>
>> libavcodec/utils.c:2102:36: warning: passing argument 1 of ???av_packet_get_side_data??? discards ???const??? qualifier from pointer target type [-Wdiscarded-qualifiers]
>
> You have an encoding problem, probably UTF-8 related, in your
> copy-paste. I suggest you re-run gcc with LC_CTYPE=C to get the error
> message in plain ASCII.

Thanks for noticing, not reproducible on the web interface:
http://git.videolan.org/?p=ffmpeg.git;a=commitdiff;h=560f5188
Same issue for 3aef2fce

> Also, lines in commit messages are usually better wrapped around 64-70
> characters.

I would prefer not to wrap gcc output.

>> ---
>>  libavcodec/avcodec.h  |    6 +++++-
>>  libavcodec/avpacket.c |    6 +++++-
>>  libavcodec/version.h  |    3 +++
>>  3 files changed, 13 insertions(+), 2 deletions(-)
>>
>> diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
>> index 925a8c7..b065309 100644
>> --- a/libavcodec/avcodec.h
>> +++ b/libavcodec/avcodec.h
>> @@ -4563,7 +4563,11 @@ int av_packet_shrink_side_data(AVPacket *pkt, enum AVPacketSideDataType type,
>>   * @param size pointer for side information size to store (optional)
>>   * @return pointer to data if present or NULL otherwise
>>   */
>> -uint8_t* av_packet_get_side_data(AVPacket *pkt, enum AVPacketSideDataType type,
>
>> +uint8_t* av_packet_get_side_data(
>> +#if FF_API_CONST_GET_SIDE_DATA
>> +const
>> +#endif
>> +                                 AVPacket *pkt, enum AVPacketSideDataType type,
>
> I do not think we need the FF_API dance, since it is not an ABI break.

I agree that there is no ABI break (but I suspect FF_API does not
imply an ABI break).

> I think is is not an API break either.

I may misremember but I thought it's an API break for c++ users.

Anyway, new patch attached.

Thank you, Carl Eugen
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