Re: Put thread in sleep mode

On Sat, 11 Aug 2007 02:12:29 +0100, MiG <miguel.a.guedes@gmail.com> wrote:


Look into multi-media timers. You should be able to have a "TimeProc" callback
called periodically with 1 ms accuracy. It'll be tough to get 60 Hz because 60
doesn't divide 1000.

This no-frills, hastily written tidbit runs a beeper ... TimeProc called every
20 ms (50 Hz) ... short beep every second ... long beep once a minute. After
about 30 minutes it does not appear to have drifted (by comparison to an analog
sweep-second wall clock). [There's no built-in way to stop it ... kill it with
TaskMgr.]

#include <windows.h>

#define WM_TICKER_SECOND WM_APP
#define WM_TICKER_MINUTE (WM_APP + 1)

void CALLBACK TimeProc(UINT uID, UINT uMsg, DWORD dwUser,
                       DWORD dw1, DWORD dw2)
{
    DWORD t = timeGetTime(),
            m = t%60000,
            s = t%1000;
    if ( m < 20 )
        PostMessage((HWND) dwUser, WM_TICKER_MINUTE, 0, 0);
    else if ( s < 20 )
        PostMessage((HWND) dwUser, WM_TICKER_SECOND, 0, 0);
}

LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg,
                            WPARAM wParam, LPARAM lParam)
{
    if ( uMsg == WM_TICKER_SECOND )
        Beep(440,100);
    else if ( uMsg == WM_TICKER_MINUTE )
        Beep(440,500);
    return DefWindowProc(hwnd, uMsg, wParam, lParam);
}

INT WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
                   LPSTR lpCmdLine, int nCmdShow)
{
    MSG msg;
    TIMECAPS tc;
    timeGetDevCaps(&tc, sizeof(TIMECAPS));
    timeBeginPeriod(tc.wPeriodMin);
    WNDCLASS WndClass = {0, WindowProc, 0, 0, hInstance,
        NULL, NULL, NULL, NULL, "HZ50_CLASS"};
    RegisterClass(&WndClass);
    HWND hwnd = CreateWindow("HZ50_CLASS", "HZ50_WINDOW", 0, 0, 0,
        0, 0, NULL, NULL, hInstance, 0);
    timeSetEvent(20, 0, TimeProc, (DWORD_PTR) hwnd, TIME_PERIODIC);
    while( GetMessage( &msg, NULL, 0, 0 ) )
        DispatchMessage(&msg);
    return msg.wParam;
}

--
 - Vince