[FFmpeg-devel] compound literal in public header file

[Tomas Härdin]

ons 2018-05-16 klockan 10:18 +0800 skrev Zhao Zhili:
> The av_err2str macro in libavutil/error.h use compound literal:
> 
> #define av_err2str(errnum) \
>      av_make_error_string((char[AV_ERROR_MAX_STRING_SIZE]){0}, 
> AV_ERROR_MAX_STRING_SIZE, errnum)
> 
> C++ compiler may not support it or treat the usage as invalid.
> For example, g++ 5.4 raise an error: taking address of temporary
> array.
> 
> 1. Should the macro be defined for C only?
> 2. Or make it as valid C++? (I don't know how to do that)

First of all, this shouldn't matter since av_err2str is not actually
used in any header. libavutil/timer.h makes use of it in another macro,
so that also doesn't matter.

Second, libavutil is a C library, not a C++ library. However, it might
be nicer to make that a static inline function, if possible. Or move it
to an internal header, since it doesn't look like something that should
be exposed as part of the public API.

/Tomas