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visual-studio-2010visual-studiozlibtinyxml

Link problems on Release x64

I have a Visual Studio 2010 C++ project that links statically to tinyxmlSTL 2.5.5 (tinyxmlSTL.lib) and zlib 1.2.7. (zlibstat.lib). There are 4 builds in total covering both x86 and x64 as well as Debug and Release.

All combinations produce working builds except for Release x64 which gets a bunch of errors like this:

MSVCRT.lib(MSVCR100.dll) : error LNK2005: free already defined in LIBCMT.lib(free.obj)

...and a single warning:

LINK : warning LNK4098: defaultlib 'MSVCRT' conflicts with use of other libs; use /NODEFAULTLIB:library

If I add /NODEFAULTLIB:MSVCRT to linker options for the application then I get this:

zlibstat.lib(ioapi.obj) : error LNK2001: unresolved external symbol __imp__ftelli64
zlibstat.lib(ioapi.obj) : error LNK2001: unresolved external symbol __imp__fseeki64

Basically, all the projects (app and two libs) are set to use Multi-threaded (/MT) option in Release builds and yet x86 builds just fine while x64 suffers from above issues.

Any help or idea is highly appreciated.

Solution

  • You need to double check your settings for x64. One of the projects is using the /MD flag rather than /MT.

    As per the MSVC docs, The MSVCRT.lib is invoked by using /MD.


    EDIT :

    As per your comments, it sounds like zlib is the likely culprit.

    zlib has both a static and dll version, but both of these use the /MD flag by default, so unless you changed that while building zlib - that's your issue.

    To build zlib using /MT:

    1. If you've not already done so, install CMake

    2. Download and extract zlib to e.g. C:\devel. The download links are about halfway down the homepage. Currently this provides zlib version 1.2.7.

    3. To work around this CMake bug, add

      if(CMAKE_SIZEOF_VOID_P EQUAL 8 AND MSVC)
  set_target_properties(zlibstatic PROPERTIES STATIC_LIBRARY_FLAGS "/machine:x64")
endif()

      to the end of C:\devel\zlib-1.2.7\CMakeLists.txt

    4. In a VS10 command prompt, cd C:\devel\zlib-1.2.7

    5. cmake -H. -Bbuild -G"Visual Studio 10 Win64"

    This gets you a VS sloution C:\devel\zlib-1.2.7\build\zlib.sln which you can open. Change the settings for the "zlibstatic" target to /MT and /MTd for Release and Debug respectively.

    Building each will yield zlibstatic.lib in a subdirectory of build; either "Release" or "Debug".