Linker error in MSVC with --disable-everything --enable-shared

[Stephen E. Baker]

Summary of the bug:
For several years I have been compiling a minimal (smacker only) version of ffmpeg for packaging with CorsixTH (an open source game implementation.)

I use vcpkg with a custom portfile to compile ffmpeg. Since updating from 3.3.5 to 4.1 my minimal compile is working; but the regular compile still works.

How to reproduce:

./configure --toolchain=msvc --prefix=../../buildtrees/ffmpeg/src --enable-asm --enable-yasm --disable-doc --enable-debug --disable-ffmpeg --enable-runtime-cpudetect --disable-openssl --disable-ffplay --disable-ffprobe --disable-libx264 --disable-opencl --disable-lzma --extra-cflags=-DHAVE_UNISTD_H=0 --disable-static --enable-shared  --extra-cflags=-MD --extra-cxxflags=-MD
make -j6

[Stephen E. Baker]

From build-x86-windows-rel-out.log:

dxva2.o : error LNK2019: unresolved external symbol impCoTaskMemFree@4 referenced in function _dxva2_create_decoder

libavcodec/avcodec-58.dll : fatal error LNK1120: 1 unresolved externals

[Carl Eugen Hoyos]

Unfortunately, the ticket title does not match the configure line you provided.
Is the issue reproducible with ./configure --toolchain=msvc --disable-everything && make ffmpeg? Or with another simplified configure line?
Please confirm that you tested current FFmpeg git head, nothing else is supported here.

[Stephen E. Baker]

Using the latest git at this time (fccba32b4c4f16682b2c34a4c84449a84f91d4d9)

I am not able to reproduce using ./configure --toolchain=msvc --disable-everything; make or ./configure --toolchain=msvc --disable-everything --disable-programs; make

I am able to reproduce with ./configure --toolchain=msvc --disable-everything --enable-asm --enable-yasm --disable-doc --enable-debug --disable-ffmpeg --enable-runtime-cpudetect --disable-openssl --disable-ffplay --disable-ffprobe --disable-libx264 --disable-opencl --disable-lzma --extra-cflags=-DHAVE_UNISTD_H=0 --disable-static --enable-shared --extra-cflags=-MD --extra-cxxflags=-MD; make

I'm not sure what the minimal necessary set of configure options is, but I know that adding --disable-autodetect, or removing --disable-everything from the last example causes it to work.

[Stephen E. Baker]

I can reproduce with:

./configure --toolchain=msvc --disable-everything --disable-doc --enable-debug --disable-programs --enable-runtime-cpudetect --disable-libx264 --disable-static --enable-shared
make

That's as far as I have time to take it tonight. If necessary I can spend some time later trying to get a true minimal set.

[Stephen E. Baker]

./configure --toolchain=msvc --disable-everything --enable-shared is the minimal set of flags to trigger the error.

In case it matters:
OS: Microsoft Windows [Version 10.0.17134.472]
Compiler: Microsoft (R) C/C++ Optimizing Compiler Version 19.15.26732.1 for x64

[Carl Eugen Hoyos]

Please run make V=1 ffmpeg.exe twice and provide the console output of the second run.

[Stephen E. Baker]

make V=1 ffmpeg.exe (second run)

[Stephen E. Baker]

Attached (ffmpeg_make.log)

[Carl Eugen Hoyos]

Please test this patch:

diff --git a/configure b/configure
index 04d3417..a636939 100755
--- a/configure
+++ b/configure
@@ -3527,7 +3527,7 @@ cws2fws_extralibs="zlib_extralibs"

 # libraries, in any order
 avcodec_deps="avutil"
-avcodec_suggest="libm"
+avcodec_suggest="libm ole32"
 avcodec_select="null_bsf"
 avdevice_deps="avformat avcodec avutil"
 avdevice_suggest="libm"
@@ -3554,7 +3554,7 @@ ffmpeg_deps="avcodec avfilter avformat"
 ffmpeg_select="aformat_filter anull_filter atrim_filter format_filter
                null_filter
                trim_filter"
-ffmpeg_suggest="ole32 psapi shell32"
+ffmpeg_suggest="psapi shell32"
 ffplay_deps="avcodec avformat swscale swresample sdl2"
 ffplay_select="rdft crop_filter transpose_filter hflip_filter vflip_filter rotate_filter"
 ffplay_suggest="shell32"

[Stephen E. Baker]

The patch fixes the error

[Carl Eugen Hoyos]

Please confirm that with this patch applied, static compilation still works: ./configure --disable-everything && make ffmpeg.exe

[Stephen E. Baker]

Confirmed

[James]

Should be fixed in 4ec2daf0de1a30bdeffbeffefcb7211e96c04980.