The J/Windows interface is referred to as the Window Driver and provides access under program control to many features of the Windows graphical and operating system environment. It provides essentially two mechanisms for communication:
wdhandler defined in script file
winlib.ijs provide these mechanisms:
wdis used to send instructions and queries to the Window Driver - and is the only way of doing so.
wdhandleris used to react to events signaled by Windows. It is the standard way of doing so, but may be changed if required.
These verbs are defined in the standard profile when you load J.