Unresolved externals from mapnik.lib

[bmharper]

After successfully building Mapnik, I'm trying to build the C++ example "rundemo.cpp". rundemo.cpp compiles fine, but when linking, I get a bunch of unresolved external symbols. I can't explain this, because when I spot check a few of these symbols, I can find them inside the exports section of mapnik.lib. Is this perhaps a VS 2015 bug that somebody has seen before?

Here is one example of a failed symbol: error LNK2001: unresolved external symbol "private: static struct std::atomic mapnik::singleton<class mapnik::datasourcecache,class mapnik::CreateStatic>::destroyed" (?destroyed_@?$singleton@Vdatasource_cache@mapnik@@VCreateStatic@2@@mapnik@@0U?$atomic@_N@std@@A)

I use dumpbin /exports mapnik.lib to discover all exported symbols, and inside it, I can find the above mentioned symbol. If it wasn't for this fact, I would keep on digging, but this has me stumped.

This is my compile line:

"C:\Program Files (x86)\Microsoft Visual Studio 14.0\vc\bin\amd64\cl.exe" /c /D_WIN32 /D__STDC_LIMIT_MACROS /DNOMINMAX /D_WIN32 /DWIN32 /D_WIN64 /DWIN64 /DNDEBUG /I"third_party\mapnik\include" /FS /W3 /EHsc /Gm- /GS /Zo /Ox /FS /MD /Zi rundemo.cpp

And this is my link line:

"C:\Program Files (x86)\Microsoft Visual Studio 14.0\vc\bin\amd64\link.exe" /DEBUG /MACHINE:X64 /NXCOMPAT /DYNAMICBASE /DEBUG /INCREMENTAL:NO /OPT:REF /OPT:ICF /RELEASE /LIBPATH:"third_party\mapnik\lib" "mapnik.lib" "msvcrt.lib" "msvcprt.lib" "comsuppw.lib" "kernel32.lib" "user32.lib" "gdi32.lib" "winspool.lib" "advapi32.lib" "shell32.lib" "comctl32.lib" "uuid.lib" "ole32.lib" "oleaut32.lib" "shlwapi.lib" "OLDNAMES.lib" "wldap32.lib" "wsock32.lib" "Psapi.lib" "Msimg32.lib" "Comdlg32.lib" "RpcRT4.lib" "Iphlpapi.lib" "Delayimp.lib" rundemo.obj /out:"rundemo.exe"

I get 50 undefined symbols. Many of them are similar to the one that I mentioned at the top of the post. My compiler version is 19.00.23506 for x64 OS is Windows 10. Branch of windows-builds is 1a23e5edd7520ab40107d8a33851bbb59d30e28b Branch of mapnik is v3.0.9

[jc101]

I had some trouble getting the demo working too but having just recompiled Mapnik from scratch, it is possible to get the demo built. (Note that I used "MAPNIKBRANCH=c786ff9edf8bb9cfd20aebe5bcdbd5a963f19e3d" as a parameter to settings.bat because of a current build breakage - see https://github.com/mapbox/windows-builds/issues/76#issuecomment-178550394)

I created the VS project as suggested in the demo c++ folder README.md, using something like

C:\python27\scripts\gyp rundemo.gyp --depth=. -f msvs -G msvs_version=2015

(Note: msvs_version needs to be changed from 2010). Then within the project I had to change the platforms from Win32 to x64. I think this may one of the sources of your problems as attempting to compile with a Win32 platform caused me 50 failed symbols.

Note that the gyp-generated project has a lot of different compile and link flags to the ones you're using which may cause other problems too. Eg for a DEBUG version I'm using:

Compiler: /GS /W1 /Zc:wchar_t /I"C:\Mapnik3\include" /I"C:\Mapnik3\include\mapnik\agg" /I"C:\Mapnik3\include\cairo" /I"C:\Mapnik3\include\freetype2" /I"C:\Mapnik3\include\google" /I"C:\Mapnik3\include\libxml2" /Zi /Gm- /O2 /Fd"Debug\obj\rundemo\vc140.pdb" /Zc:inline /fp:precise /D "LINUX" /D "_WINDOWS" /D "BOOST_ALL_NO_LIB" /D "BOOST_MSVC_ENABLE_2014_JUN_CTP" /D "BOOST_VARIANT_DO_NOT_USE_VARIADIC_TEMPLATES" /D "HAVE_JPEG" /D "HAVE_PNG" /D "HAVE_WEBP" /D "HAVE_TIFF" /D "MAPNIK_USE_PROJ4" /D "BOOST_REGEX_HAS_ICU" /D "GRID_RENDERER" /D "SVG_RENDERER" /D "MAPNIK_THREADSAFE" /D "BIGINT" /D "HAVE_LIBXML2" /D "HAVE_CAIRO" /D "LIBXML_STATIC" /errorReport:prompt /WX- /Zc:forScope /Gd /MD /Fa"Debug\obj\rundemo\" /EHsc /nologo /Fo"Debug\obj\rundemo\" /Fp"Debug\obj\rundemo\rundemo.pch"

Linker /OUT:"C:\Mapnik3\demo\c++\Debug\rundemo.exe" /MANIFEST /NXCOMPAT /PDB:"C:\Mapnik3\demo\c++\Debug\rundemo.pdb" /DYNAMICBASE "mapnik.lib" "boost_python-vc140-mt-1_59.lib" "cairo-static.lib" "cairo.lib" "freetype.lib" "gdal_i.lib" "harfbuzz.lib" "icudt.lib" "icuin.lib" "icuuc.lib" "jpeg.lib" "libboost_chrono-vc140-mt-1_59.lib" "libboost_date_time-vc140-mt-1_59.lib" "libboost_filesystem-vc140-mt-1_59.lib" "libboost_iostreams-vc140-mt-1_59.lib" "libboost_prg_exec_monitor-vc140-mt-1_59.lib" "libboost_program_options-vc140-mt-1_59.lib" "libboost_regex-vc140-mt-1_59.lib" "libboost_system-vc140-mt-1_59.lib" "libboost_test_exec_monitor-vc140-mt-1_59.lib" "libboost_thread-vc140-mt-1_59.lib" "libboost_timer-vc140-mt-1_59.lib" "libboost_unit_test_framework-vc140-mt-1_59.lib" "libboost_zlib-vc140-mt-1_59.lib" "libexpat.lib" "libpng16.lib" "libpq.lib" "libprotobuf-lite.lib" "libtiff_i.lib" "libwebp_dll.lib" "mapnik-json.lib" "mapnik-wkt.lib" "proj.lib" "python27.lib" "sqlite3.lib" "zlib.lib" "zlibwapi.lib" "ws2_32.lib" /DEBUG /MACHINE:X64 /PGD:"C:\Mapnik3\demo\c++\Debug\rundemo.pgd" /MANIFESTUAC:"level='asInvoker' uiAccess='false'" /ManifestFile:"Debug\obj\rundemo\rundemo.exe.intermediate.manifest" /ERRORREPORT:PROMPT /NOLOGO /LIBPATH:"C:\Mapnik3\lib" /TLBID:1

I also needed to make some changes to the source code: hardcoding the datasource and font paths in lines 57 and 58:

datasource_cache::instance().register_datasources("C:\\mapnik3\\lib\\mapnik\\input"); freetype_engine::register_font("C:\\mapnik3\\lib\\mapnik\\fonts\\DejaVuSans.ttf");

and commenting out the p["encoding"] bits at lines 233 and 298.

Finally, you should run the executable from the top level Mapnik folder or change the layer paths on eg lines 232, 246, etc.

[wilhelmberg]

Sorry, I missed this issue. @jc101 thanks for reporting, will look into it. BTW: latest master should be good to go again. Just had a successful build.

[bmharper]

Thanks so much for the detailed post(s). I'll try tonight when I'm at that machine again, and post my feedback here.

[bmharper]

Thanks again for the help. I've managed to get the demo building. For the record, I was missing two crucial #defines: "_WINDOWS" and "BIGINT". It's really my fault not trying the gyp route first, and checking it's build configuration output.