This command-line tool shows the handles of all open windows.
The tool can also be used to show only information relating to a
specific process, object type,
or object name. This feature is useful for finding the process that
has a file open when a sharing violation occurs.
To function properly, OH must enable a kernel option that
maintains a linked list of all objects sorted by object type. If
the kernel option is not turned on, OH enables the kernel option
and notifies you to restart the computer so that OH functions and
displays information.
A handle is a 32-bit positive integer that Windows uses
to identify a window or other object, such as a font or bitmap.
In Windows, a window is any window that you see on the
screen as well as many objects that you cannot see. A window can be
a bounded rectangular area of the screen (such as a Microsoft Word
window) or a control on a form (such as a list box or a scroll bar)
although not all types of controls are windows. The desktop and the
icons that appear on it are windows.
Because all of these types of objects are windows, Windows can
treat them similarly. Windows gives every window a unique handle
when it is created and uses that handle to control that window.
When the window is destroyed, Windows frees the handle it used to
control the window. A window retains the same handle during its
lifetime, but each time the window is recreated, a new handle is
assigned. In other words, a window probably will not have the same
handle if it is destroyed and recreated.
