Gets status on AutoCAD LT  LTCustomizer21 for AutoCAD LT reference manual

ActiveX
    Function IsRunningCAD() As Boolean
    Function ready() As Boolean
C/C++
    int WINAPI LTC_IsRunningCAD();
    int WINAPI LTC_ready();

return value
True or 1: LTCustomizer21 can communicate with AutoCAD LT.
False or 0: LTCustomizer21 cannot communicate with AutoCAD LT.

IsRunningCAD() distinguish whether LTCustomizer21 communicate with AutoCAD LT. ready() is the same IsRunningCAD() basically, but ready() is attempt to communicate with AutoCAD LT when AutoCAD LT is terminated and then run. If there is description of running CAD in LTC21.cfg, attempt to communicate with the CAD after LTCustomizer21 made the specified CAD run automatically. (About description of LTC21.cfg, see init()
So you should execute ready() or IsRunnningCAD() before other LTCustomizer21 functions execute except initializing.