fixed libtest linker error on msvc

[snikulov]

The issue:

first.obj : error LNK2019: unresolved external symbol snprintf referenced in function hexdump [\curl\b\tests\libtest\lib526.vcxproj]
  C:\WORK\GITHUB\dev\curl\b\tests\libtest\Release\lib526.exe : fatal error LNK1120: 1 unresolved externals [\curl\b\tests\libtest\lib526.vcxproj]

How to reproduce:

cmake .. -G"Visual Studio 11 Win64"
cmake --build . --config Release

Suggested solution:
mprintf.h header added to test.h to prevent future issues in libtest

[gvanem]

IMHO, adding -Dsnprintf=_snprintf to the CFLAGS would be cleaner. I don't know how since CMake is gibberish to me.

[snikulov]

@gvanem according to documentation _snprintf has different semantic from snprintf (for example http://stackoverflow.com/questions/7706936/is-snprintf-always-null-terminating/13067917#13067917). If this not important I can do the trick with little update in CMakeLists.txt

Waiting for more comments.

[gvanem]

I don't think snprintf() vs. _snprintf() matters for libtests/*.c files.

[bagder]

Your patch removes the use of the internal snprintf(), why does that solve the problem? Why shouldn't the windows built versions also use that?

[snikulov]

@bagder it not removes. I include it in single place test.h and remove duplication.

[bagder]

Ah, thanks for clearing that out. I was clearly not reading the whole patch. With me being corrected. I can't see any problems with this patch!

[bagder]

Oh, unless of course you build with CURLDEBUG defined. It shows we have some further cleaning up work to do... (use of sprintf() that we frown upon)

[snikulov]

Ok. Will check it soon. Perhaps I'll need also update cmake build to honor CURLDEBUG option, because I'm not currently aware of that.

[bagder]

Ah right. With the configure build you use --enable-debug to switch it on, and it enables extra debugging info, checks and outputs in various way.

[snikulov]

Well, some clarification --enable-curldebug - enables TrackMemory feature, while --enable-debug - enables both (Debug && TrackMemory). Am I correct?

Another question - should it be wirtten to curlbuild.h or as autoconfig do - just set definition to Makefiles?

[snikulov]

I've submitted another pull request #145 to handle CURLDEBUG define for build in cmake.

[snikulov]

@bagder what should we do, when CURLDEBUG enabled?
Code from mprintf.h will definetely break the build

#ifdef CURLDEBUG
/* When built with CURLDEBUG we define away the sprintf functions since we
don't want internal code to be using them */
# define sprintf sprintf_was_used
# define vsprintf vsprintf_was_used
#else
# define sprintf curl_msprintf
# define vsprintf curl_mvsprintf
#endif

[bagder]

I think that since curl/mprintf.h is a public header, it should not feature that #ifdef in the first place. I think I'll help out here and move that debug-#define sequence into a private libcurl header instead.

[bagder]

Thanks, I cleaned up the include thing first, then merged your patch!