| HDC GetDC(hwnd) | ||||
| HWND hwnd; | /* handle of window, */ | |||
The GetDC function retrieves the handle of a device context for the client area of the given window. The device context can be used in subsequent graphics device interface (GDI) functions to draw in the client area.
The GetDC function retrieves a common, class, or private device context, depending on the class style specified for the given window. For common device contexts, GetDC assigns default attributes to the context each time it is retrieved. For class and private contexts, GetDC leaves the previously assigned attributes unchanged.
hwnd
Identifies the window where drawing will occur. If this parameter is NULL, the function returns a device context for the screen.
The return value is a handle of the device context for the given window's client area, if the function is successful. Otherwise, it is NULL.
Unless the device context belongs to a window class, the ReleaseDC function must be called to release the context after drawing. Since only five common device contexts are available at any given time, failure to release a device context can prevent other applications from accessing a device context. If the hwnd parameter of the GetDC function is NULL, the first parameter of ReleaseDC should also be NULL.
A device context belonging to the window's class is returned by the GetDC function if CS_CLASSDC, CS_OWNDC, or CS_PARENTDC style was specified in the WNDCLASS structure when the class was registered.