原帖（修正）：http://www.oioj.net/blog/new3/foxxp/archives/2007/365923.shtml

#include <windows.h>
#include <tchar.h>

//Functions & other definitions required-->
typedef int (__stdcall *MSGBOXAAPI)(IN HWND hWnd,
        IN LPCSTR lpText, IN LPCSTR lpCaption,
        IN UINT uType, IN WORD wLanguageId, IN DWORD dwMilliseconds);
typedef int (__stdcall *MSGBOXWAPI)(IN HWND hWnd,
        IN LPCWSTR lpText, IN LPCWSTR lpCaption,
        IN UINT uType, IN WORD wLanguageId, IN DWORD dwMilliseconds);

int MessageBoxTimeoutA(IN HWND hWnd, IN LPCSTR lpText,
    IN LPCSTR lpCaption, IN UINT uType,
    IN WORD wLanguageId, IN DWORD dwMilliseconds);
int MessageBoxTimeoutW(IN HWND hWnd, IN LPCWSTR lpText,
    IN LPCWSTR lpCaption, IN UINT uType,
    IN WORD wLanguageId, IN DWORD dwMilliseconds);

#ifdef UNICODE
    #define MessageBoxTimeout MessageBoxTimeoutW
#else
    #define MessageBoxTimeout MessageBoxTimeoutA
#endif

#define MB_TIMEDOUT 32000

int MessageBoxTimeoutA(HWND hWnd, LPCSTR lpText,
    LPCSTR lpCaption, UINT uType, WORD wLanguageId,
    DWORD dwMilliseconds)
{
    static MSGBOXAAPI MsgBoxTOA = NULL;

    if (!MsgBoxTOA)
    {
        HMODULE hUser32 = GetModuleHandle(_T("user32.dll"));
        if (hUser32)
        {
            MsgBoxTOA = (MSGBOXAAPI)GetProcAddress(hUser32,
                                      "MessageBoxTimeoutA");
            //fall through to 'if (MsgBoxTOA)...'
        }
        else
        {
            //stuff happened, add code to handle it here
            //(possibly just call MessageBox())
            return 0;
        }
    }

    if (MsgBoxTOA)
    {
        return MsgBoxTOA(hWnd, lpText, lpCaption,
              uType, wLanguageId, dwMilliseconds);
    }

    return 0;
}

int MessageBoxTimeoutW(HWND hWnd, LPCWSTR lpText,
    LPCWSTR lpCaption, UINT uType, WORD wLanguageId, DWORD dwMilliseconds)
{
    static MSGBOXWAPI MsgBoxTOW = NULL;

    if (!MsgBoxTOW)
    {
        HMODULE hUser32 = GetModuleHandle(_T("user32.dll"));
        if (hUser32)
        {
            MsgBoxTOW = (MSGBOXWAPI)GetProcAddress(hUser32,
                                      "MessageBoxTimeoutW");
            //fall through to 'if (MsgBoxTOW)...'
        }
        else
        {
            //stuff happened, add code to handle it here
            //(possibly just call MessageBox())
            return 0;
        }
    }

    if (MsgBoxTOW)
    {
        return MsgBoxTOW(hWnd, lpText, lpCaption,
               uType, wLanguageId, dwMilliseconds);
    }

    return 0;
}
//End required definitions <--
//Call the function as follows:

// Collapse
//you must load user32.dll before calling the function
main()
{
	HMODULE hUser32 = LoadLibrary(_T("user32.dll"));

	if (hUser32)
	{
		 int iRet = 0;
		 UINT uiFlags = MB_OK|MB_SETFOREGROUND|MB_SYSTEMMODAL|MB_ICONINFORMATION;

		 iRet = MessageBoxTimeout(NULL, _T("Test a timeout of 2 seconds."),
								 _T("MessageBoxTimeout Test"), uiFlags, 0, 2000);
		 //iRet will = 1

		 uiFlags = MB_YESNO|MB_SETFOREGROUND|MB_SYSTEMMODAL|MB_ICONINFORMATION;

		 iRet = MessageBoxTimeout(NULL, _T("Test a timeout of 5 seconds."),
								 _T("MessageBoxTimeout Test"), uiFlags, 0, 5000);
		 //iRet will = MB_TIMEDOUT if no buttons pressed, button values otherwise

		 //only unload user32.dll when you have no further need
		 //for the MessageBoxTimeout function
		 FreeLibrary(hUser32);
	}
}