Qt 5.11.3 works fine, but Qt 5.12.1 throws LINKER errors
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On Windows 10, Qt 5.11.3 builds my application without any issue. However Qt 5.12.1, throws LINKER errors:
main.obj : error LNK2019: unresolved external symbol "__declspec(dllimport) void __cdecl NetLibrary::registerNetLibraryQML(void)" (_imp?registerNetLibraryQML@NetLibrary@@YAXXZ) referenced in function main
debug\application.exe : fatal error LNK1120: 1 unresolved externalsmy
main.cppis like:#include "../netlib/netlib.h" int main(int argc, char *argv[]) { // ... NetLibrary::registerNetLibraryQML(); // ... }My
netlib.hcontains:namespace NetLibrary { NETLIBSHARED_EXPORT void registerNetLibraryQML(); }And my
netlib.cppcontains:namespace NetLibrary { NETLIBSHARED_EXPORT void registerNetLibraryQML() { static bool registered = false; if (!registered) { qmlRegisterType<Netlib>("com.application.Application", 1, 0, "Netlib"); registered = true; } } }I wonder why Qt 5.11.3 has no linker issue, but Qt 5.12.1 runs into errors.
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So how to you link against the netlib library? Are you sure the netlib library is linked with the same compiler as Qt?
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The linking to net-library is done inside
*.profile:win32:CONFIG(release, debug|release): LIBS += -L$$OUT_PWD/../netlib/release/ -lnetlib else:win32:CONFIG(debug, debug|release): LIBS += -L$$OUT_PWD/../netlib/debug/ -lnetlib else:unix: LIBS += -L$$OUT_PWD/../netlib/ -lnetlib INCLUDEPATH += $$PWD/../netlib DEPENDPATH += $$PWD/../netlib -
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MSVC needs the correct path instead -L and -l afaik
https://doc.qt.io/qt-5/qmake-variable-reference.html#libs -
Thanks :) The strange point is that I have two more libraries which I'm linking against with the same approach without any issue. But only this
net libraryis giving me troubles! -
Maybe the function is not properly exported? Maybe take a look at the exported function declarations with Dependency Walker - make sure the export string (_imp?registerNetLibraryQML@NetLibrary@@YAXXZ) shown there looks exactly the same.
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Good idea :) I'm going to employ dependency walker tools
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I double-checked my
netlibDLL with dependency walker, I can see the export:
Also, on my
main.objI can see the import:
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I've no idea - does the linker really links against the import lib? Are other functions from within the library are resolved?
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@m3g1dd While checking the
netlibDLL is a good thing for avoiding failures when launching your application.exe (when the .dll is loaded), here the error occurs not when running the app, but when linking it, So the .dll is immaterial, you could instead check thenetlib.libfile, that's what the linker is reading.Dependency Walker isn't well suited for reading .lib files, but there's a tool in MSVC2017 called
dumpbin, easiest is to start it from a Developer Command Prompt for VS 2017. To get the complete information, use the /linkermember switch, say like this:dumpbin /linkermember netlib.libThen check in the list if that symbol is exported, it should be 2 of them, one __imp?registerNetLibraryQML@NetLibrary@@YAXXZ and one ?registerNetLibraryQML@NetLibrary@@YAXXZ
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Thanks! I run the command on Developer Command Prompt for VS 2017 and I get the results, I can see both
?registerNetLibraryQML@NetLibrary@@YAXXZand__imp_?registerNetLibraryQML@NetLibrary@@YAXXZexpressions:C:\Users\me\repos\build-application-Desktop_Qt_5_12_1_MSVC2017_64bit-Debug\netlib\debug>dumpbin /linkermember netlib.lib Microsoft (R) COFF/PE Dumper Version 14.15.26730.0 Copyright (C) Microsoft Corporation. All rights reserved. Dump of file netlib.lib File Type: LIBRARY Archive member name at 8: / FFFFFFFF time/date uid gid 0 mode C3D size correct header end 69 public symbols 190A __IMPORT_DESCRIPTOR_netlib 1B30 __NULL_IMPORT_DESCRIPTOR 1C66 netlib_NULL_THUNK_DATA 2878 ?registerNetLibraryQML@NetLibrary@@YAXXZ 2878 __imp_?registerNetLibraryQML@NetLibrary@@YAXXZ 2E0C ?tr@Netlib@@SA?AVQString@@PEBD0H@Z 2E0C __imp_?tr@Netlib@@SA?AVQString@@PEBD0H@Z 2E8A ?trUtf8@Netlib@@SA?AVQString@@PEBD0H@Z 2E8A __imp_?trUtf8@Netlib@@SA?AVQString@@PEBD0H@Z 1DBE ??0Netlib@@QEAA@XZ 1DBE __imp_??0Netlib@@QEAA@XZ 1E2C ??1Netlib@@UEAA@XZ 1E2C __imp_??1Netlib@@UEAA@XZ 1F06 ?agentDiscover@Netlib@@QEAAXXZ 1F06 __imp_?agentDiscover@Netlib@@QEAAXXZ 1FFA ?agentSlice@Netlib@@QEAA_NAEBVQUrl@@AEBVQString@@V3@222@Z 1FFA __imp_?agentSlice@Netlib@@QEAA_NAEBVQUrl@@AEBVQString@@V3@222@Z 210E ?discoveryInProgress@Netlib@@QEBA_NXZ 210E __imp_?discoveryInProgress@Netlib@@QEBA_NXZ 28FC ?setDiscoveryInProgress@Netlib@@QEAAX_N@Z 28FC __imp_?setDiscoveryInProgress@Netlib@@QEAAX_N@Z 2C7E ?slicingInProgress@Netlib@@QEBA_NXZ 2C7E __imp_?slicingInProgress@Netlib@@QEBA_NXZ 2A82 ?setSlicingInProgress@Netlib@@QEAAX_N@Z 2A82 __imp_?setSlicingInProgress@Netlib@@QEAAX_N@Z 2530 ?layerID@Netlib@@QEBA?AVQString@@XZ 2530 __imp_?layerID@Netlib@@QEBA?AVQString@@XZ 2982 ?setLayerID@Netlib@@QEAAXVQString@@@Z 2982 __imp_?setLayerID@Netlib@@QEAAXVQString@@@Z 2B82 ?slicingDone@Netlib@@QEBA_NXZ 2B82 __imp_?slicingDone@Netlib@@QEBA_NXZ 2A04 ?setSlicingDone@Netlib@@QEAAX_N@Z 2A04 __imp_?setSlicingDone@Netlib@@QEAAX_N@Z 24BE ?init@Netlib@@AEAAXXZ 24BE __imp_?init@Netlib@@AEAAXXZ 22AA ?getOsName@Netlib@@AEAA?AVQString@@XZ 22AA __imp_?getOsName@Netlib@@AEAA?AVQString@@XZ 2090 ?discoveryFinished@Netlib@@AEAAXXZ 2090 __imp_?discoveryFinished@Netlib@@AEAAXXZ 2B06 ?slicerFinished@Netlib@@AEAAXXZ 2B06 __imp_?slicerFinished@Netlib@@AEAAXXZ 1F80 ?agentLogReady@Netlib@@AEAAXXZ 1F80 __imp_?agentLogReady@Netlib@@AEAAXXZ 2430 ?handleSlicingInProgressChanged@Netlib@@AEAAX_N@Z 2430 __imp_?handleSlicingInProgressChanged@Netlib@@AEAAX_N@Z 232C ?getSlicerProgress@Netlib@@AEAAXXZ 232C __imp_?getSlicerProgress@Netlib@@AEAAXXZ 23AA ?getSlicerProgressFinished@Netlib@@AEAAXXZ 23AA __imp_?getSlicerProgressFinished@Netlib@@AEAAXXZ 1E9A __imp_??_7Netlib@@6B@ 2636 ?metaObject@Netlib@@UEBAPEBUQMetaObject@@XZ 2636 __imp_?metaObject@Netlib@@UEBAPEBUQMetaObject@@XZ 2752 ?qt_metacast@Netlib@@UEAAPEAXPEBD@Z 2752 __imp_?qt_metacast@Netlib@@UEAAPEAXPEBD@Z 26BE ?qt_metacall@Netlib@@UEAAHW4Call@QMetaObject@@HPEAPEAX@Z 26BE __imp_?qt_metacall@Netlib@@UEAAHW4Call@QMetaObject@@HPEAPEAX@Z 27D2 ?qt_static_metacall@Netlib@@CAXPEAVQObject@@W4Call@QMetaObject@@HPEAPEAX@Z 27D2 __imp_?qt_static_metacall@Netlib@@CAXPEAVQObject@@W4Call@QMetaObject@@HPEAPEAX@Z 2190 ?discoveryInProgressChanged@Netlib@@QEAAX_N@Z 2190 __imp_?discoveryInProgressChanged@Netlib@@QEAAX_N@Z 221A ?discoveryResultChanged@Netlib@@QEAAXVQJsonArray@@@Z 221A __imp_?discoveryResultChanged@Netlib@@QEAAXVQJsonArray@@@Z 2CFE ?slicingInProgressChanged@Netlib@@QEAAX_N@Z 2CFE __imp_?slicingInProgressChanged@Netlib@@QEAAX_N@Z 25B0 ?layerIDChanged@Netlib@@QEAAXVQString@@@Z 25B0 __imp_?layerIDChanged@Netlib@@QEAAXVQString@@@Z 2BFC ?slicingDoneChanged@Netlib@@QEAAX_N@Z 2BFC __imp_?slicingDoneChanged@Netlib@@QEAAX_N@Z 2D86 __imp_?staticMetaObject@Netlib@@2UQMetaObject@@B Archive member name at C82: / FFFFFFFF time/date uid gid 0 mode C4B size correct header end 37 offsets 1 190A 2 1B30 3 1C66 4 2878 5 2E0C 6 2E8A 7 1DBE 8 1E2C 9 1F06 A 1FFA B 210E C 28FC D 2C7E E 2A82 F 2530 10 2982 11 2B82 12 2A04 13 24BE 14 22AA 15 2090 16 2B06 17 1F80 18 2430 19 232C 1A 23AA 1B 1E9A 1C 2636 1D 2752 1E 26BE 1F 27D2 20 2190 21 221A 22 2CFE 23 25B0 24 2BFC 25 2D86 69 public symbols 7 ??0Netlib@@QEAA@XZ 8 ??1Netlib@@UEAA@XZ 9 ?agentDiscover@Netlib@@QEAAXXZ 17 ?agentLogReady@Netlib@@AEAAXXZ A ?agentSlice@Netlib@@QEAA_NAEBVQUrl@@AEBVQString@@V3@222@Z 15 ?discoveryFinished@Netlib@@AEAAXXZ B ?discoveryInProgress@Netlib@@QEBA_NXZ 20 ?discoveryInProgressChanged@Netlib@@QEAAX_N@Z 21 ?discoveryResultChanged@Netlib@@QEAAXVQJsonArray@@@Z 14 ?getOsName@Netlib@@AEAA?AVQString@@XZ 19 ?getSlicerProgress@Netlib@@AEAAXXZ 1A ?getSlicerProgressFinished@Netlib@@AEAAXXZ 18 ?handleSlicingInProgressChanged@Netlib@@AEAAX_N@Z 13 ?init@Netlib@@AEAAXXZ F ?layerID@Netlib@@QEBA?AVQString@@XZ 23 ?layerIDChanged@Netlib@@QEAAXVQString@@@Z 1C ?metaObject@Netlib@@UEBAPEBUQMetaObject@@XZ 1E ?qt_metacall@Netlib@@UEAAHW4Call@QMetaObject@@HPEAPEAX@Z 1D ?qt_metacast@Netlib@@UEAAPEAXPEBD@Z 1F ?qt_static_metacall@Netlib@@CAXPEAVQObject@@W4Call@QMetaObject@@HPEAPEAX@Z 4 ?registerNetLibraryQML@NetLibrary@@YAXXZ C ?setDiscoveryInProgress@Netlib@@QEAAX_N@Z 10 ?setLayerID@Netlib@@QEAAXVQString@@@Z 12 ?setSlicingDone@Netlib@@QEAAX_N@Z E ?setSlicingInProgress@Netlib@@QEAAX_N@Z 16 ?slicerFinished@Netlib@@AEAAXXZ 11 ?slicingDone@Netlib@@QEBA_NXZ 24 ?slicingDoneChanged@Netlib@@QEAAX_N@Z D ?slicingInProgress@Netlib@@QEBA_NXZ 22 ?slicingInProgressChanged@Netlib@@QEAAX_N@Z 5 ?tr@Netlib@@SA?AVQString@@PEBD0H@Z 6 ?trUtf8@Netlib@@SA?AVQString@@PEBD0H@Z 1 __IMPORT_DESCRIPTOR_netlib 2 __NULL_IMPORT_DESCRIPTOR 7 __imp_??0Netlib@@QEAA@XZ 8 __imp_??1Netlib@@UEAA@XZ 1B __imp_??_7Netlib@@6B@ 9 __imp_?agentDiscover@Netlib@@QEAAXXZ 17 __imp_?agentLogReady@Netlib@@AEAAXXZ A __imp_?agentSlice@Netlib@@QEAA_NAEBVQUrl@@AEBVQString@@V3@222@Z 15 __imp_?discoveryFinished@Netlib@@AEAAXXZ B __imp_?discoveryInProgress@Netlib@@QEBA_NXZ 20 __imp_?discoveryInProgressChanged@Netlib@@QEAAX_N@Z 21 __imp_?discoveryResultChanged@Netlib@@QEAAXVQJsonArray@@@Z 14 __imp_?getOsName@Netlib@@AEAA?AVQString@@XZ 19 __imp_?getSlicerProgress@Netlib@@AEAAXXZ 1A __imp_?getSlicerProgressFinished@Netlib@@AEAAXXZ 18 __imp_?handleSlicingInProgressChanged@Netlib@@AEAAX_N@Z 13 __imp_?init@Netlib@@AEAAXXZ F __imp_?layerID@Netlib@@QEBA?AVQString@@XZ 23 __imp_?layerIDChanged@Netlib@@QEAAXVQString@@@Z 1C __imp_?metaObject@Netlib@@UEBAPEBUQMetaObject@@XZ 1E __imp_?qt_metacall@Netlib@@UEAAHW4Call@QMetaObject@@HPEAPEAX@Z 1D __imp_?qt_metacast@Netlib@@UEAAPEAXPEBD@Z 1F __imp_?qt_static_metacall@Netlib@@CAXPEAVQObject@@W4Call@QMetaObject@@HPEAPEAX@Z 4 __imp_?registerNetLibraryQML@NetLibrary@@YAXXZ C __imp_?setDiscoveryInProgress@Netlib@@QEAAX_N@Z 10 __imp_?setLayerID@Netlib@@QEAAXVQString@@@Z 12 __imp_?setSlicingDone@Netlib@@QEAAX_N@Z E __imp_?setSlicingInProgress@Netlib@@QEAAX_N@Z 16 __imp_?slicerFinished@Netlib@@AEAAXXZ 11 __imp_?slicingDone@Netlib@@QEBA_NXZ 24 __imp_?slicingDoneChanged@Netlib@@QEAAX_N@Z D __imp_?slicingInProgress@Netlib@@QEBA_NXZ 22 __imp_?slicingInProgressChanged@Netlib@@QEAAX_N@Z 25 __imp_?staticMetaObject@Netlib@@2UQMetaObject@@B 5 __imp_?tr@Netlib@@SA?AVQString@@PEBD0H@Z 6 __imp_?trUtf8@Netlib@@SA?AVQString@@PEBD0H@Z 3 netlib_NULL_THUNK_DATA Summary C0 .debug$S 14 .idata$2 14 .idata$3 8 .idata$4 8 .idata$5 C .idata$6 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Thanks! Yes, other functions of
netlibare linked fine. I will update if I figure out the cause :) -
Hi! Thanks for follow up :)
For Qt 5.11.3 I'm using
MSVC2017_64bitwhich works fine. My build directories are:build-application-Desktop_Qt_5_11_3_MSVC2017_64bit-Debug build-application-Desktop_Qt_5_11_3_MSVC2017_64bit-Release build-application-Desktop_Qt_5_12_1_MSVC2017_64bit-Debug -
Hmm, just to check again: release builds and debug builds on 5.12.0 MSVC 2017 links fine and dandy, but the same linker throws a tantrum both for release and debug builds on 5.12.1 MSVC 2017.
Also, could do you a similar dumpbin on a 5.12.0 debug built netlib.lib as you did above for a 5.12.1 debug build?
