I have two machines, one running Vista Ultimate 32, the other one running XP SP3. both machines have the same VS2008 version installed.
I built boost 1.50.0 on the first machine (vista), and subsequently libtorrent library, that relies on boost.
I saw in some libtorrent build instructions that the win version is specified within preprocessor, so I did what seemed to make sense at the moment:
#define _WIN32_WINNT=0x0600 // being that the current OS is Vista
The build went successfully, and I was able to run the application on that machine. However, when I tried to run it on the other one (XP), it failed with the message, something like:
Procedure entry point SetFileInformationByHandle could not be located in the dynamic link library KERNEL32.dll
Now, logically, I'm guessing that this has something to do with incompatible versions, and probably different windows headers are included when this variable exists with different values.
The requirement: I'd like to build this on Vista or 7, and still be able to run it on XPs.
The question: Do I need this directive at all, and if I do, what should be the value? What else should I specify, if I'm missing something?
Try to build your program on XP or set _WIN32_WINNT to 0x0501 (as in your comment). The kernel32.dll library is backward binary compatible according to this report, so you can build your program with old version of this library (5.0) and run it with a new one (6.0) without the need to recompile. Vice versa is not possible due to a bunch of added symbols (SetFileInformationByHandle is one of them).