Unresolved-symbol error when linking Qt application to Google Breakpad

I'm trying to statically link my Qt application to Google Breakpad under Windows but I always get unresolved symbol errors. I'm using qmake and VC++2008 and there seems to be some problem with my project file. It seems like if the linker was ignoring my LIBS specification because I get the error no matter I add the library to LIBS or not.

I compiled Breakpad using:

vcbuild /platform:Win32

Google Breakpead includes an example in src\processor\test_app.cc. If I compile it as suggested, everything goes fine:

C:\test>cl /Zi test_app.cc /Fetest_app.exe /I C:\google-breakpad\src C:\google-breakpad\src\client\windows\Release\lib\exception_handler.lib C:\google-breakpad\src\client\windows\Release\lib\crash_generation_client.lib C:\google-breakpad\src\client\windows\Release\lib\common.lib

However, if I try to build it with qmake using a similar .pro file I get the same unresolved symbol errors. This is the .pro file I use for it:

TEMPLATE = app
TARGET = 
DEPENDPATH += .
INCLUDEPATH += .
INCLUDEPATH += C:/google-breakpad/src
SOURCES += test_app.cc

LIBS += C:/google-breakpad/src/client/windows/Release/lib/exception_handler.lib
LIBS += C:/google-breakpad/src/client/windows/Release/lib/crash_generation_client.lib
LIBS += C:/google-breakpad/src/client/windows/Release/lib/common.lib
PRE_TARGETDEPS += C:/google-breakpad/src/client/windows/Release/lib/exception_handler.lib
PRE_TARGETDEPS += C:/google-breakpad/src/client/windows/Release/lib/crash_generation_client.lib
PRE_TARGETDEPS += C:/google-breakpad/src/client/windows/Release/lib/common.lib

Building it:

C:\test>qmake -config release

C:\test>nmake

Microsoft (R) Program Maintenance Utility Version 9.00.21022.08
Copyright (C) Microsoft Corporation.  All rights reserved.

        "C:\Program files\Microsoft Visual Studio 9.0\VC\BIN\nmake.exe" -
f Makefile.Release

Microsoft (R) Program Maintenance Utility Version 9.00.21022.08
Copyright (C) Microsoft Corporation.  All rights reserved.

        cl -c -nologo -Zm200 -Zc:wchar_t- -O2 -MD -GR -EHsc -W3 -w34100 -w34189
-DUNICODE -DWIN32 -DQT_LARGEFILE_SUPPORT -DQT_DLL -DQT_NO_DEBUG -DQT_GUI_LIB -DQ
T_CORE_LIB -DQT_HAVE_MMX -DQT_HAVE_3DNOW -DQT_HAVE_SSE -DQT_HAVE_MMXEXT -DQT_HAV
E_SSE2 -DQT_THREAD_SUPPORT -I"..\Qt\4.7.1\include\QtCore" -I"..\Qt\4.7.1\include
\QtGui" -I"..\Qt\4.7.1\include" -I"." -I"..\google-breakpad\src" -I"..\Qt\4.7.1\
include\ActiveQt" -I"release" -I"..\Qt\4.7.1\mkspecs\win32-msvc2008" -Forelease\
 @C:\Windows\Temp\nm94.tmp
test_app.cc
.\test_app.cc(43) : warning C4100: 'assertion' : unreferenced formal parameter
.\test_app.cc(42) : warning C4100: 'exinfo' : unreferenced formal parameter
.\test_app.cc(42) : warning C4100: 'context' : unreferenced formal parameter
.\test_app.cc(41) : warning C4100: 'dump_path' : unreferenced formal parameter
.\test_app.cc(62) : warning C4100: 'argv' : unreferenced formal parameter
.\test_app.cc(62) : warning C4100: 'argc' : unreferenced formal parameter
        link /LIBPATH:"c:\Qt\4.7.1\lib" /NOLOGO /INCREMENTAL:NO /MANIFEST /MANIF
ESTFILE:"release\test.intermediate.manifest" /SUBSYSTEM:WINDOWS "/MANIFESTDEPEND
ENCY:type='win32' name='Microsoft.Windows.Common-Controls' version='6.0.0.0' pu开发者_JAVA百科b
licKeyToken='6595b64144ccf1df' language='*' processorArchitecture='*'" /OUT:rele
ase\test.exe @C:\Windows\Temp\nm95.tmp
LINK : warning LNK4098: defaultlib 'LIBCMT' conflicts with use of other libs; us
e /NODEFAULTLIB:library
test_app.obj : error LNK2019: unresolved external symbol "public: __thiscall goo
gle_breakpad::ExceptionHandler::ExceptionHandler(class std::basic_string<unsigne
d short,struct std::char_traits<unsigned short>,class std::allocator<unsigned sh
ort> > const &,bool (__cdecl*)(void *,struct _EXCEPTION_POINTERS *,struct MDRawA
ssertionInfo *),bool (__cdecl*)(unsigned short const *,unsigned short const *,vo
id *,struct _EXCEPTION_POINTERS *,struct MDRawAssertionInfo *,bool),void *,int)"
 (??0ExceptionHandler@google_breakpad@@QAE@ABV?$basic_string@GU?$char_traits@G@s
td@@V?$allocator@G@2@@std@@P6A_NPAXPAU_EXCEPTION_POINTERS@@PAUMDRawAssertionInfo
@@@ZP6A_NPBG5123_N@Z1H@Z) referenced in function _main
release\test.exe : fatal error LNK1120: 1 unresolved externals
NMAKE : fatal error U1077: '"C:\Program files\Microsoft Visual Studio 9.0\VC\BIN
\link.EXE"' : return code '0x460'
Stop.
NMAKE : fatal error U1077: '"C:\Program files\Microsoft Visual Studio 9.0\VC\BIN
\nmake.exe"' : return code '0x2'
Stop.

What am I missing in the .pro file?

Thanks in advance.

The issue is that the Google Breakpad library is compiled with "Treat wchar_t as Built-in Type" enabled (/Zc:wchar_t). Qt compiles with that option disabled (/Zc:wchar_t-). This means that at compile time, everything matches up: the std::wstring is defined in terms of unsigned short, which is what Qt expects. But at link time, the Breakpad library has defined wstring in terms of __wchar_t (or wchar_t). The effect is that the linker cannot resolve your call to their function, since the parameter types to not match (at link time.)

The solution is to either:

• disable the "Treat wchar_t as Built-in Type" in the Google Breakpad library (under Configuration Properties > C/C++ > Language. (This is what we are trying...)
• enable the option in Qt (remove /Zc:wchar_t-)

For more information:

• /Zc:wchar_t (wchar_t Is Native Type)

(This one is subtle; had us stumped for the greater part of a day.)