[FFmpeg-devel] mingw64 4.7.x struct alignment behavior has changed

Gianluigi Tiesi mplayer at netfarm.it
Fri Jan 10 02:53:10 CET 2014


Sorry for cross posting but it's related both to mplayer/ffmpeg

as stated in this announce:
http://cygwin.com/ml/cygwin-announce/2013-07/msg00011.html

For gcc-4.7.x, struct alignment behavior has changed, -mms-bitfields is
now default for better MSVC compatibility. This may cause ABI changes
in libraries that expose data structures directly to clients. Workaround
include marking the struct with the gcc_struct attributes.

this actually breaks mplayer libmpdemux/asf.h structs

e.g. ASF_stream_header_t is 56 bytes instead of 54

I'm not sure about other places in mplayer and/or ffmpeg
I'm not even sure for libraries I build for dependencies

Should we add explicit gcc_struct or pass -mno-ms-bitfields to mingw?

Regards

-- 
Gianluigi Tiesi <sherpya at netfarm.it>
EDP Project Leader
Netfarm S.r.l. - http://www.netfarm.it/
Free Software: http://oss.netfarm.it/


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