* commit 'c0329748b04e1f175dad8c9c2ebf22a5e2dc5b72':
fate: add a dependency helper macro
Add support for building shared libraries with MSVC
avcodec: Rename avpriv_frame_rate_tab to ff_mpeg12_frame_rate_tab
gxf: Add a local copy of the relevant parts of the frame rate table
configure: Split out msvc as a separate target OS
aviobuf: Remove a senseless ifdef in avio_seek
Conflicts:
configure
libavcodec/dirac.c
libavcodec/mpeg12data.h
libavcodec/mpeg12enc.c
Merged-by: Michael Niedermayer <michaelni@gmx.at>
This requires the makedef perl script by Derek, from the
c89-to-c99 repo. That scripts produces a .def file, listing
the symbols to be exported, based on the gcc version scripts
and the built object files.
To properly load non-function symbols from DLL files, the
data symbol declarations need to have the attribute
__declspec(dllimport) when building the calling code. (On mingw,
the linker can fix this up automatically, which is why it has not
been an issue so far. If this attribute is omitted, linking
actually succeeds, but reads from the table will not produce the
desired results at runtime.)
MSVC seems to manage to link DLLs (and run properly) even if
this attribute is present while building the library itself
(which normally isn't recommended) - other object files in the
same library manage to link to the symbol (with a small warning
at link time, like "warning LNK4049: locally defined symbol
_avpriv_mpa_bitrate_tab imported" - it doesn't seem to be possible
to squelch this warning), and the definition of the tables
themselves produce a warning that can be squelched ("warning C4273:
'avpriv_mpa_bitrate_tab' : inconsistent dll linkage, see previous
definition of 'avpriv_mpa_bitrate_tab').
In this setup, mingw isn't able to link object files that refer to
data symbols with __declspec(dllimport) without those symbols
actually being linked via a DLL (linking avcodec.dll ends up with
errors like "undefined reference to `__imp__avpriv_mpa_freq_tab'").
The dllimport declspec isn't needed at all in mingw, so we simply
choose not to declare it for other compilers than MSVC that requires
it. (If ICL support later requires it, the condition can be extended
later to include both of them.)
This also implies that code that is built to link to a certain
library as a DLL can't link to the same library as a static library.
Therefore, we only allow building either static or shared but not
both at the same time. (That is, static libraries as such can be,
and actually are, built - this is used for linking the test tools to
internal symbols in the libraries - but e.g. libavformat built to
link to libavcodec as a DLL cannot link statically to libavcodec.)
Also, linking to DLLs is slightly different from linking to shared
libraries on other platforms. DLLs use a thing called import
libraries, which is basically a stub library allowing the linker
to know which symbols exist in the DLL and what name the DLL will
have at runtime.
In mingw/gcc, the import library is usually named libfoo.dll.a,
which goes next to a static library named libfoo.a. This allows
gcc to pick the dynamic one, if available, from the normal -lfoo
switches, just as it does for libfoo.a vs libfoo.so on Unix. On
MSVC however, you need to literally specify the name of the import
library instead of the static library.
Signed-off-by: Martin Storsjö <martin@martin.st>
* qatar/master:
dca: Switch dca_sample_rates to avpriv_ prefix; it is used across libs
ARM: use =const syntax instead of explicit literal pools
ARM: use standard syntax for all LDRD/STRD instructions
fft: port FFT/IMDCT 3dnow functions to yasm, and disable on x86-64.
dct-test: allow to compile without HAVE_INLINE_ASM.
x86/dsputilenc: bury inline asm under HAVE_INLINE_ASM.
dca: Move tables used outside of dcadec.c to a separate file.
dca: Rename dca.c ---> dcadec.c
x86: h264dsp: Remove unused variable ff_pb_3_1
apetag: change a forgotten return to return 0
Conflicts:
libavcodec/Makefile
libavcodec/dca.c
libavcodec/x86/fft_3dn.c
libavcodec/x86/fft_3dn2.c
libavcodec/x86/fft_mmx.asm
Merged-by: Michael Niedermayer <michaelni@gmx.at>
Consistently apply this rule: the guard name is obtained from the
filename by stripping the leading "lib", converting '/' and '.' to
'_' and uppercasing the resulting name. Guard names in the root
directory have to be prefixed by "FFMPEG_".
Originally committed as revision 15120 to svn://svn.ffmpeg.org/ffmpeg/trunk
