1，涉及API

GetNativeSystemInfo 原型：

void WINAPI GetNativeSystemInfo(
  _Out_  LPSYSTEM_INFO lpSystemInfo
);

这个函数在kernel32.dll中。

SYSTEM_INFO 结构：

typedef struct _SYSTEM_INFO {
    union {
        DWORD dwOemId;          		// 已废弃的成员，保留这个成员是为了向以前版本的Windows NT保持兼容
        struct {
            WORD wProcessorArchitecture;	//指定系统中的中央处理器的体系结构
            WORD wReserved;
        };
    };
    DWORD dwPageSize;
    LPVOID lpMinimumApplicationAddress;
    LPVOID lpMaximumApplicationAddress;
    DWORD_PTR dwActiveProcessorMask;
    DWORD dwNumberOfProcessors;
    DWORD dwProcessorType;
    DWORD dwAllocationGranularity;
    WORD wProcessorLevel;
    WORD wProcessorRevision;
} SYSTEM_INFO, *LPSYSTEM_INFO;

2，使用

判断系统是否为64位系统的函数：

BOOL Is64BitSystem()
{
	SYSTEM_INFO si;
	FUN_GetNativeSystemInfo pfn = (FUN_GetNativeSystemInfo)GetProcAddress(GetModuleHandle("kernel32.dll"), "GetNativeSystemInfo");
	if (pfn)
	{
		pfn(&si);
		
		if (si.wProcessorArchitecture == PROCESSOR_ARCHITECTURE_AMD64 ||    
			si.wProcessorArchitecture == PROCESSOR_ARCHITECTURE_IA64 )
		{
			return TRUE;
		}
	}
	return FALSE;	
}

当然，目前不是64位，应该可以说就是32位系统了，可以直接写出获取系统位数的函数：

int GetSystemBits()
{
	SYSTEM_INFO si;
	FUN_GetNativeSystemInfo pfn = (FUN_GetNativeSystemInfo)GetProcAddress(GetModuleHandle("kernel32.dll"), "GetNativeSystemInfo");
	if (pfn)
	{
		pfn(&si);
		
		if (si.wProcessorArchitecture == PROCESSOR_ARCHITECTURE_AMD64 ||    
			si.wProcessorArchitecture == PROCESSOR_ARCHITECTURE_IA64 )
		{
			return 64;
		}
	}
	return 32;	
}