[FFmpeg-devel] [PATCH 1/2] libavutil: Add av_visibility_hidden for setting hidden symbol visibility

[Martin Storsjö]

On Mon, 11 Jul 2022, Andreas Rheinhardt wrote:

> Martin Storsjö:
>> Signed-off-by: Martin Storsjö <martin at martin.st>
>> ---
>>  doc/APIchanges         | 3 +++
>>  libavutil/attributes.h | 6 ++++++
>>  libavutil/version.h    | 2 +-
>>  3 files changed, 10 insertions(+), 1 deletion(-)
>> 
>> diff --git a/doc/APIchanges b/doc/APIchanges
>> index 20b944933a..5d84bc27d7 100644
>> --- a/doc/APIchanges
>> +++ b/doc/APIchanges
>> @@ -14,6 +14,9 @@ libavutil:     2021-04-27
>>
>>  API changes, most recent first:
>> 
>> +2022-xx-xx - xxxxxxxxxx - lavu 57.28.100 - attributes.h
>> +  Add av_visibility_hidden, for setting hidden visibilty on symbols.
>> +
>>  2022-06-12 - xxxxxxxxxx - lavf 59.25.100 - avio.h
>>    Add avio_vprintf(), similar to avio_printf() but allow to use it
>>    from within a function taking a variable argument list as input.
>> diff --git a/libavutil/attributes.h b/libavutil/attributes.h
>> index 04c615c952..dc4c88932c 100644
>> --- a/libavutil/attributes.h
>> +++ b/libavutil/attributes.h
>> @@ -170,4 +170,10 @@
>>  #    define av_noreturn
>>  #endif
>> 
>> +#if (AV_GCC_VERSION_AT_LEAST(4,0) || defined(__clang__)) && (defined(__ELF__) || defined(__MACH__))
>> +#    define av_visibility_hidden __attribute__((visibility("hidden")))
>> +#else
>> +#    define av_visibility_hidden
>> +#endif
>> +
>>  #endif /* AVUTIL_ATTRIBUTES_H */
>> diff --git a/libavutil/version.h b/libavutil/version.h
>> index 2e9e02dda8..87178e9e9a 100644
>> --- a/libavutil/version.h
>> +++ b/libavutil/version.h
>> @@ -79,7 +79,7 @@
>>   */
>>
>>  #define LIBAVUTIL_VERSION_MAJOR  57
>> -#define LIBAVUTIL_VERSION_MINOR  27
>> +#define LIBAVUTIL_VERSION_MINOR  28
>>  #define LIBAVUTIL_VERSION_MICRO 100
>>
>>  #define LIBAVUTIL_VERSION_INT   AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \
>
> Hidden stuff is by definition not part of installed headers, so that
> there is no point in adding a public define for this.

Good point - attribute.h would otherwise have been the natural spot, but I 
agree that it'd be better to not make it public at all. In what header 
would you prefer to have it?

// Martin