Thread: Updating without pressing a button

Hi everyone,

I have a program which takes the current system time, and displays it as year, month, day, hour, minute and second. At the moment, it updates the time when you press an 'update' button. However, I want to make it automatically update the time without the user pressing the 'update' button. Here's the program I have now:

Code:

#include <windows.h>
#include <math.h>
#include <cmath>
#include <cstdio>
#include "resource.h" 

BOOL CALLBACK ToolDlgProc(HWND hwnd, UINT Message, WPARAM wParam, LPARAM lParam)
{
	switch(Message)
	{
		case WM_COMMAND:
			switch(LOWORD(wParam))
			{

			case IDC_UPDATE:

				SYSTEMTIME* p_st = new SYSTEMTIME;
                GetSystemTime(p_st);
                double year = p_st->wYear;
                double month = p_st->wMonth;
                double day = p_st->wDay;
                double hour = p_st->wHour;
				double minute = p_st->wMinute;
				double second = p_st->wSecond;

                char strYear[100];
				sprintf_s(strYear,"%0.0f", year);
				SetDlgItemText(hwnd, IDC_YEAR, strYear);

				char strMonth[100];
				sprintf_s(strMonth,"%0.0f", month);
				SetDlgItemText(hwnd, IDC_MONTH, strMonth);

				char strDay[100];
				sprintf_s(strDay,"%0.0f", day);
				SetDlgItemText(hwnd, IDC_DAY, strDay);

				char strHour[100];
				sprintf_s(strHour,"%0.0f", hour);
				SetDlgItemText(hwnd, IDC_HOUR, strHour);

				char strMinute[100];
				sprintf_s(strMinute,"%0.0f", minute);
				SetDlgItemText(hwnd, IDC_MINUTE, strMinute);

				char strSecond[100];
				sprintf_s(strSecond,"%0.0f", second);
				SetDlgItemText(hwnd, IDC_SECOND, strSecond);

				break;	

			}
		break;

		case WM_CLOSE:
			EndDialog(hwnd, 0);
		    break;

		default:
			return FALSE;
	}
	return TRUE;
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
	LPSTR lpCmdLine, int nCmdShow)
{
	return DialogBox(hInstance, MAKEINTRESOURCE(IDD_CLOCK), NULL, ToolDlgProc);
}

As you can see, when the user presses IDC_UPDATE, the date and time will update. How could I implement a loop which automatically updates? I could use a while loop in a console program, but that doesn't work here.

Thanks a lot.

I'm not getting any errors for sprintf_s - I had no idea I was doing it wrong!

I'm compiling using visual C++ (if this makes a difference) and I don't get any warnings either.

Originally Posted by Elysia

Warnings, not errors, since I assume you're compiling in C.
Take a good look: sprintf_s, _sprintf_s_l, swprintf_s, _swprintf_s_l
It wants at least 4 parameters. You are giving it 3.

Originally Posted by MSDN

In C++, using these functions is simplified by template overloads; the overloads can infer buffer length automatically (eliminating the need to specify a size argument) and they can automatically replace older, non-secure functions with their newer, secure counterparts. For more information, see Secure Template Overloads.

The preprocessor macro is

Code:

#define __DEFINE_CPP_OVERLOAD_SECURE_FUNC_0_1_ARGLIST(_ReturnType, _FuncName, _VFuncName, _DstType, _Dst, _TType1, _TArg1) \
    extern "C++" \
    { \
	__pragma(warning(push)); \
	__pragma(warning(disable: 4793)); \
    template <size_t _Size> \
    inline \
    _ReturnType __CRTDECL _FuncName(_DstType (&_Dst)[_Size], _TType1 _TArg1, ...) _CRT_SECURE_CPP_NOTHROW \
    { \
        va_list _ArgList; \
        _crt_va_start(_ArgList, _TArg1); \
        return _VFuncName(_Dst, _Size, _TArg1, _ArgList); \
    } \
	__pragma(warning(pop)); \
    }

__DEFINE_CPP_OVERLOAD_SECURE_FUNC_0_1_ARGLIST(int, sprintf_s, vsprintf_s, _Deref_post_z_ char, _Dest, _In_z_ _Printf_format_string_ const char *, _Format)

This is my real code - I promise! Of course I have the resource file and the header file too, but that's it. I'm compiling as a multi-threaded debug, but other than that, the settings are as default (using VC++ 2008 express).

Originally Posted by Elysia

_Mike: First I heard of that. Mystery unraveled then!

Yeah I found it by accident when rewriting some of my code a while back.
I changed a char[] to char* and all of a sudden it wouldn't compile anymore because I had forgotten the size parameter for swprintf_s earlier

I'm looking to use C++ please.