windows下C++判断32位和64位

1.在Windows 64bit系统开发程序时, 某些情况需要判断Program Files路径, 但是64bit系统有两个Program Files或 Program Files(x86), 这时候就需要根据当前系统的位数来获取路径了.

说明

1.通过判断程序是32bit或64bit并没有什么用,因为64bit系统可以运行32bit和64bit程序.

2.64bit系统的kernel32.dll 里有一个函数接口 IsWow64Process,只需要判断这个dll是否有这个导出函数即可.

例子

// test-OSBit.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include <Windows.h>
#include "Shlobj.h"
#include <iostream>


typedef BOOL (WINAPI *LPFN_ISWOW64PROCESS) (HANDLE, PBOOL);

static LPFN_ISWOW64PROCESS fnIsWow64Process = NULL;

//
//   FUNCTION: SafeIsWow64Process(HANDLE, PBOOL)
//
//   PURPOSE: This is a wrapper of the IsWow64Process API. It determines 
//   whether the specified process is running under WOW64. IsWow64Process 
//   does not exist prior to Windows XP with SP2 and Window Server 2003  with 
//   SP1. For compatibility with operating systems that do not support 
//   IsWow64Process, call GetProcAddress to detect whether IsWow64Process is 
///  implemented in Kernel32.dll. If GetProcAddress succeeds, it is safe to 
//   call IsWow64Process dynamically. Otherwise, WOW64 is not present.
//
//   PARAMETERS:
//   * hProcess - A handle to the process. 
//   * Wow64Process - A pointer to a value that is set to TRUE if the process 
//     is running under WOW64. If the process is running under 32-bit Windows, 
//     the value is set to FALSE. If the process is a 64-bit application 
//     running under 64-bit Windows, the value is also set to FALSE.
//
//   RETURN VALUE: If the function succeeds, the return value is TRUE.If 
//   IsWow64Process does not exist in kernel32.dll, or the function fails, 
//   the return value is FALSE. 
//
static BOOL WINAPI SafeIsWow64Process(HANDLE hProcess, PBOOL Wow64Process)
{
    if (fnIsWow64Process == NULL)
    {
        // IsWow64Process is not available on all supported versions of 
        // Windows. Use GetModuleHandle to get a handle to the DLL that 
        // contains the function, and GetProcAddress to get a pointer to the 
        // function if available.
        HMODULE hModule = GetModuleHandle(L"kernel32.dll");
        if (hModule == NULL)
        {
            return FALSE;
        }

        fnIsWow64Process = reinterpret_cast<LPFN_ISWOW64PROCESS>(
            GetProcAddress(hModule, "IsWow64Process"));
        if (fnIsWow64Process == NULL)
        {
            return FALSE;
        }
    }
    return fnIsWow64Process(hProcess, Wow64Process);
}

//
//   FUNCTION: Is64BitOS()
//
//   PURPOSE: The function determines whether the current operating system is 
//   a 64-bit operating system.
//
//   RETURN VALUE: The function returns TRUE if the operating system is 
//   64-bit; otherwise, it returns FALSE.
//
static BOOL Is64BitOS()
{
#if defined(_WIN64)
    return TRUE;   // 64-bit programs run only on Win64
#elif defined(_WIN32)
    // 32-bit programs run on both 32-bit and 64-bit Windows
    BOOL f64bitOS = FALSE;
    return (SafeIsWow64Process(GetCurrentProcess(), &f64bitOS) && f64bitOS);
#else
    return FALSE;  // 64-bit Windows does not support Win16
#endif
}

int _tmain(int argc, _TCHAR* argv[])
{
    TCHAR folder[MAX_PATH] = {0};
    if(Is64BitOS())
        ::SHGetSpecialFolderPath(NULL,folder,CSIDL_PROGRAM_FILESX86,FALSE);
    else
        ::SHGetSpecialFolderPath(NULL,folder,CSIDL_PROGRAM_FILES,FALSE);
    std::wcout << "32bit Program Files: " << folder << std::endl;
    system("pause");
    return 0;
}