Using the Windows 8 SDK to compile for Windows 7

Question

(This question uses zlib as an example but isn't specific to it.)

I'm trying to compile zlib on Windows using the MSVC project file it comes with. I'm using VS2012 with the Windows 8 SDK, but my build machine is Windows 7.

Zlib contains the following code:

#ifdef IOWIN32_USING_WINRT_API
    if ((filename!=NULL) && (dwDesiredAccess != 0))
        hFile = CreateFile2((LPCTSTR)filename, dwDesiredAccess, dwShareMode, dwCreationDisposition, NULL);
#else
    if ((filename!=NULL) && (dwDesiredAccess != 0))
        hFile = CreateFile((LPCTSTR)filename, dwDesiredAccess, dwShareMode, NULL, dwCreationDisposition, dwFlagsAndAttributes, NULL);
#endif

where IOWIN32_USING_WINRT_API is set up as follows

#if defined(WINAPI_FAMILY_PARTITION) && (!(defined(IOWIN32_USING_WINRT_API)))
#if WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_APP)
#define IOWIN32_USING_WINRT_API 1
#endif
#endif

WINAPI_FAMILY_PARTITION and WINAPI_PARTITION_APP are defined in the Windows 8 SDK (winapifamily.h), so the result is that the code that uses CreateFile2 in zlib is available to be compiled.

I can compile zlib, but any application that tries to load it fails because it can't find CreateFile2, and rightly so, since my machine is Windows 7 and that API was introduced in Windows 8.

This is the first time I've ever used a Windows SDK on a lower version of Windows than it supports, hence my question:

Is my only recourse to patch zlib to add a check for _WIN32_WINNT >= _WIN32_WINNT_WIN8 to the very first line, and pass /D_WIN32_WINNT=_WIN32_WINNT_WIN7 to msbuild? That would mean I'd have to build two sets of binaries - one that supports Win7 (by passing the /D) and one that supports Win8 (by not passing the /D).

Is there no way to have a common binary that works on both Windows 7 and 8 and uses the CreateFile2 codepath if running on Windows 8? (I suppose that way is GetProcAddress + function pointers. Anything else?)

Answer 1

You can use _WIN32_WINNT to select which OS version you want to target. It's the zlib check which is broken. WINAPI_FAMILY_DESKTOP_APP includes WINAPI_FAMILY_APP so their check always succeeds. You can fix it like:

#if defined(WINAPI_FAMILY_PARTITION) && (!(defined(IOWIN32_USING_WINRT_API)))
#if WINAPI_FAMILY_ONE_PARTITION(WINAPI_FAMILY_DESKTOP_APP, WINAPI_PARTITION_APP)
#define IOWIN32_USING_WINRT_API 1
#endif
#endif

See here for more info: http://social.msdn.microsoft.com/Forums/en-US/winappswithnativecode/thread/3965645c-978c-4148-b32c-1853f7fd22b3

Answer 2

This question is old but if anyone still has this problem, I just succeded building latest zlib with msvc 12.0 targeting windows 7 by modifying the code in (iowin32.c file line 28) like so:

#if _WIN32_WINNT >= _WIN32_WINNT_WIN8
#if defined(WINAPI_FAMILY_PARTITION) && (!(defined(IOWIN32_USING_WINRT_API)))
#if WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_APP)
#define IOWIN32_USING_WINRT_API 1
#endif
#endif
#endif

of course to make this work you need to define a macro in: configuration properties >C/C++ > preprocessor:

_WIN32_WINNT=0x0601

which means you're targeting windows 7 (if using windows 7 SDK this is not needed)

then rebuilding the project with success :) and yes, of course this fix is only aplicable if you're using a windows older than windows 8.

however this is not the only error that zlib has, you will for sure encounter a mismatched version in zlib.def file. to fix this open the zlib.def file that contains the error and replace 1.2.8 with 1.28 or whatever the version is