Windows API Reference

Documentation for Windows Developers

API Constants

System Information

SM_CXSCREEN
0

Width of the screen in pixels.

System Information

SM_CYSCREEN
1

Height of the screen in pixels.

System Information

SM_CXVSCROLL
2

Width of the vertical scroll bar arrow bitmap in pixels.

System Information

SM_CYVSCROLL
3

Height of the vertical scroll bar arrow bitmap in pixels.

Window Styles

WS_OVERLAPPED
0x00000000L

Creates a top-level window. Has a system-defined icon, class, and base window procedure. The window has a title bar (if the WS_CAPTION style is also specified).

Window Styles

WS_POPUP
0x80000000L

Creates a pop-up window. This style cannot be used with the WS_CHILD style.

Window Styles

WS_CHILD
0x40000000L

Creates a child window. This window is owned by another window.

Window Styles

WS_VISIBLE
0x10000000L

Creates a window that is initially visible.

Window Styles

WS_DISABLED
0x08000000L

Creates a window that is initially disabled. Disabled windows cannot receive input from the user.

Messages

WM_PAINT
0x000F

The WM_PAINT message is generated whenever a portion of a window's client area needs to be repainted.

Messages

WM_SIZE
0x0005

The WM_SIZE message is sent to a window after its size changes.

Messages

WM_KEYDOWN
0x0100

The WM_KEYDOWN message is posted to the input queue when a key is pressed.

Messages

WM_LBUTTONDOWN
0x0201

The WM_LBUTTONDOWN message is generated when the user presses the left mouse button.

Graphics Modes

GM_SETHOOK
1

Sets a hook to receive graphics mode notifications.

Graphics Modes

GM_GETTRANSFORM
3

Gets the current graphics transform matrix.

Error Codes

ERROR_SUCCESS
0

The operation completed successfully.

Error Codes

ERROR_INVALID_HANDLE
6

The handle is invalid.

Error Codes

ERROR_FILE_NOT_FOUND
2

The system cannot find the file specified.