When function mt_ApplInit() is invoqued to initiate a GEM/WinDom session, an instance of this structure is created. This data describes the GEM application and contains informations about the process itself, the GEM environnement and some variables which are used to parametrize some functions and WinDom behavior.
Almost WinDom functions require, as first parameter, an application descriptor, i.e. a pointer to an APPvar variable. Most of time, application descriptor is the current application process. However WinDom can run in a multi-thread environment and this parameter can address an another application (a thread for example).
Only pipe and evnt fields can be written. Other fields are set by mt_ApplInit() and should not be modified.