Unresolved external symbol main referenced in function WinMain

[pauljurczak]

Describe the bug I described this issue in https://stackoverflow.com/questions/70269013/using-vcpkg-with-visual-studio-2022-produces-a-bogus-unresolved-external-symbol

I have an MFC C++ project, which builds and runs just fine with Visual Studio 2022 on Windows 10. The project doesn't use Qt at all. After I installed Qt 6.2.1 with vcpkg, project stopped building with this linker error:

1>Qt6EntryPoint.lib(qtentrypoint_win.cpp.obj) : error LNK2019: unresolved external symbol main referenced in function WinMain

I had to disable vcpkg -> Use Autolink in order to build the project after Qt installation.

Environment

• Windows 10
• Visual Studio 2022 v17.0.2

[JackBoosY]

Can you provide the file list in _VCPKGROOT/installed/TRIPLET/lib?

Thanks.

[pauljurczak]

Here is the list:

C:\src\vcpkg\installed\x64-windows\lib>dir
 Volume in drive C has no label.
 Volume Serial Number is B6C2-9CE0

 Directory of C:\src\vcpkg\installed\x64-windows\lib

12/14/2021  09:12 PM    <DIR>          .
12/14/2021  09:12 PM    <DIR>          ..
12/06/2021  11:24 PM             3,514 brotlicommon.lib
12/06/2021  11:24 PM             4,546 brotlidec.lib
12/06/2021  11:24 PM             4,082 brotlienc.lib
12/06/2021  11:24 PM             6,224 bz2.lib
12/06/2021  11:25 PM           861,964 double-conversion.lib
12/06/2021  11:25 PM            48,624 freetype.lib
12/06/2021  11:27 PM             4,538 harfbuzz-subset.lib
12/06/2021  11:27 PM           100,554 harfbuzz.lib
12/06/2021  11:38 PM             1,686 icudt.lib
12/06/2021  11:38 PM         2,842,346 icuin.lib
12/06/2021  11:38 PM            12,584 icuio.lib
12/06/2021  11:38 PM            70,118 icutu.lib
12/06/2021  11:38 PM         1,072,514 icuuc.lib
12/06/2021  09:08 PM         7,237,716 imgui.lib
12/02/2021  12:38 PM            24,808 jpeg.lib
12/06/2021  11:42 PM         1,011,470 libcrypto.lib
12/06/2021  11:45 PM             7,198 libecpg.lib
12/06/2021  11:45 PM             9,086 libecpg_compat.lib
12/06/2021  11:45 PM         1,938,284 libpgcommon.lib
12/06/2021  11:45 PM         3,038,190 libpgport.lib
12/06/2021  11:45 PM            12,358 libpgtypes.lib
12/02/2021  12:39 PM            55,894 libpng16.lib
12/06/2021  11:45 PM            34,772 libpq.lib
12/02/2021  12:41 PM           941,662 libprotobuf-lite.lib
12/02/2021  12:43 PM         3,979,550 libprotobuf.lib
12/02/2021  12:43 PM           431,192 libprotoc.lib
12/06/2021  11:42 PM           121,986 libssl.lib
12/02/2021  12:40 PM             7,126 libwebpmux.lib
12/14/2021  09:12 PM         2,319,956 lodepng.lib
12/02/2021  12:39 PM            23,422 lzma.lib
12/07/2021  12:16 AM    <DIR>          metatypes
12/02/2021  12:56 PM           283,172 opencv_calib3d.lib
12/02/2021  12:50 PM           854,112 opencv_core.lib
12/02/2021  12:55 PM           570,550 opencv_dnn.lib
12/02/2021  12:55 PM           297,338 opencv_features2d.lib
12/02/2021  12:50 PM           144,820 opencv_flann.lib
12/02/2021  12:52 PM           203,850 opencv_highgui.lib
12/02/2021  12:52 PM           147,936 opencv_imgcodecs.lib
12/02/2021  12:52 PM           307,176 opencv_imgproc.lib
12/02/2021  12:52 PM           186,444 opencv_ml.lib
12/02/2021  12:56 PM           326,000 opencv_objdetect.lib
12/02/2021  12:53 PM           234,810 opencv_photo.lib
12/02/2021  12:56 PM           785,922 opencv_stitching.lib
12/02/2021  12:56 PM           365,434 opencv_video.lib
12/02/2021  12:52 PM           197,778 opencv_videoio.lib
12/06/2021  11:46 PM            20,424 pcre2-16.lib
12/06/2021  11:46 PM            20,424 pcre2-32.lib
12/06/2021  11:46 PM            19,974 pcre2-8.lib
12/06/2021  11:46 PM             2,362 pcre2-posix.lib
12/07/2021  02:00 PM    <DIR>          pkgconfig
12/07/2021  12:04 AM            13,042 Qt6Concurrent.lib
12/07/2021  12:15 AM               177 Qt6Concurrent.prl
12/07/2021  12:04 AM         2,821,286 Qt6Core.lib
12/07/2021  12:15 AM               168 Qt6Core.prl
12/07/2021  12:06 AM           172,192 Qt6DBus.lib
12/07/2021  12:15 AM               165 Qt6DBus.prl
12/07/2021  12:05 AM           876,542 Qt6DeviceDiscoverySupport.lib
12/07/2021  12:15 AM               352 Qt6DeviceDiscoverySupport.prl
12/07/2021  12:02 AM            54,012 Qt6EntryPoint.lib
12/07/2021  12:15 AM               243 Qt6EntryPoint.prl
12/07/2021  12:08 AM         5,179,142 Qt6FbSupport.lib
12/07/2021  12:15 AM               511 Qt6FbSupport.prl
12/07/2021  12:08 AM         3,594,118 Qt6Gui.lib
12/07/2021  12:15 AM               163 Qt6Gui.prl
12/07/2021  12:05 AM           603,278 Qt6Network.lib
12/07/2021  12:15 AM               171 Qt6Network.prl
12/07/2021  12:09 AM         6,641,114 Qt6OpenGL.lib
12/07/2021  12:15 AM               169 Qt6OpenGL.prl
12/07/2021  12:12 AM            15,252 Qt6OpenGLWidgets.lib
12/07/2021  12:15 AM               183 Qt6OpenGLWidgets.prl
12/07/2021  12:12 AM           182,690 Qt6PrintSupport.lib
12/07/2021  12:15 AM               181 Qt6PrintSupport.prl
12/07/2021  12:04 AM           174,210 Qt6Sql.lib
12/07/2021  12:15 AM               163 Qt6Sql.prl
12/07/2021  12:08 AM            82,856 Qt6Test.lib
12/07/2021  12:15 AM               168 Qt6Test.prl
12/07/2021  12:11 AM         3,104,762 Qt6Widgets.lib
12/07/2021  12:15 AM               171 Qt6Widgets.prl
12/07/2021  12:04 AM            97,846 Qt6Xml.lib
12/07/2021  12:15 AM               163 Qt6Xml.prl
12/02/2021  12:43 PM           204,142 quirc.lib
12/06/2021  11:47 PM            65,204 sqlite3.lib
12/02/2021  12:44 PM            38,380 tiff.lib
12/02/2021  12:38 PM             9,196 turbojpeg.lib
12/02/2021  12:40 PM            19,162 webp.lib
12/02/2021  12:39 PM            10,756 webpdecoder.lib
12/02/2021  12:40 PM             6,372 webpdemux.lib
12/07/2021  02:00 PM           111,192 yaml-cpp.lib
12/02/2021  12:39 PM            16,334 zlib.lib
12/06/2021  11:47 PM            42,848 zstd.lib
              88 File(s)     55,335,566 bytes
               4 Dir(s)  36,762,054,656 bytes free

[JackBoosY]

@Neumann-A This file should be put into folder manual-link.

[XERGER]

Got the same error, not even moving the lib to the manual-link folder helped.

Does someone have an idea how it can be solved?

Just trying to build a simple CMake qt app.

Qt6EntryPoint.lib(qtentrypoint_win.cpp.obj) : error LNK2019: unresolved external symbol main referenced in function Win Main [E:\demo_cmake\tmp\cache\InformationServer\builds\win32\App\App.vcxproj]

qt_standard_project_setup() add_executable(${PROJECT_NAME} WIN32 ${Includes})

[JackBoosY]

cc @LilyWangLL

[roel-v]

Any news on this? I ran into the same issue - installed vcpkg & the Qt it provides on my machine, all of a sudden my regular projects stop building.

[jdoubleu]

I'm facing the same issue on version 2024.02.14.

My MFC project seems to pull in the Qt6EntryPoint.lib. That is, because it defines/exports WinMain. However I would expect it to select WinMain from MFC. It is probably an ordering issue, where vcpkg libraries take precedence over MFC (or Windows SDK) libraries?

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