Question

I am writing a software using Qt. One of my task is to judge whether Windows OS is 32bit or 64bit, and then do the following operations according this fact.

However, when I was trying “QSysInfo::WordSize“, it always return 32 while I was actually running on Windows 7-64 bit OS.
I also tried

#ifdef _WIN32
return 32;
#elif _WIN64
return 64;

This also returns 32.

Actually Qt is 32bit in my system. Is that the problem?
How can I get the actual word size of Windows?

Thanks

Answer 1

I personally would call GetNativeSystemInfo and check the value of the wProcessorArchitecture field.

The _WIN32 and _WIN64 macros are, like all macros, evaluated at compile time. They tell you about the architecture of your executable file rather than the architecture of the system on which the executable runs. That latter information, the information that you want, can only be determined at runtime.