Turn off the monitor?

Question

I have windows 10 64 bit,and i spend a lot of time programming behind the screen.I need to take break from time to time,and limit the screen light/radiation from colliding with my head by making the screen turn black,as if turned off.

What i am capable of doing is dropping to login screen,but i need to see it BLACK to be relieved! What am really hoping to achieve is the black screen that you get when inactive for sometime.Can i do it programmatically?

Here's the code I've had so far:

#include <Windows.h>

#define KEY_DOWN(key) ((::GetAsyncKeyState(key) & 0x80000) ? 1 : 0)
#define KEY_UP(key)   ((::GetAsyncKeyState(key) & 0x80000) ? 0 : 1)

int main(void)
{
    // Hide the console window
    HWND hWnd;
    AllocConsole();
    hWnd = FindWindowA("ConsoleWindowClass", NULL);
    ShowWindow(hWnd, 0);

    //Press ctrl + alt + 'L' to lock / Press ctrl + 'E' to terminate the program
    while (1)
    {
        if (::GetAsyncKeyState('L') == -32767)
        {
            if (KEY_DOWN(VK_CONTROL) && KEY_DOWN(VK_MENU))
                LockWorkStation();
        }
        if (::GetAsyncKeyState('E') == -32767)
        {
            if (KEY_DOWN(VK_CONTROL))
                return 0;
        }
    }
    return 0;
}

Answer 1

Use the SC_MONITORPOWER parameter for the WM_SYSCOMMAND message to turn off the monitor:

SendMessage(handle, WM_SYSCOMMAND, SC_MONITORPOWER, 2);

The argument 2 for the fourth parameter turns the monitor off.

See also https://msdn.microsoft.com/en-us/library/windows/desktop/ms646360(v=vs.85).aspx