TABLE OF CONTENTS Although VBA programs run inside of AutoCAD, they also run inside of windows, and there are times when an application needs to perform tasks related to the operating system. This is where VBA greatly exceeds the abilities of AutoLISP. You can talk to Windows by calling functions that are available as objects and utilities to your programs.
API is an acronym for Application Programmer's Interface. The Windows Application Programmer's Interface is a set of functions built into Windows that allow you to access the system's registry and INI files. Microsoft has included a robust set of information about the system in the registry, and you can write more exotic applications using this information. You can write sound generator programs or programs that animate the desktop or draw on it. Windows API is a whole world unto itself, and many a career has been made learning and using it.
AutoLISP programmers have not been able to access the Windows registry and therefore have limited or no experience with this rich environment. You can access any information stored in the registry through the API calls. This includes ActiveX information about other applications or even information about your printer or plotter. It all depends on the vendor setting up the information in the registry.
An example is AutoCAD and AutoCAD LT. AutoCAD is an ActiveX client and server. It can make calls to other applications, or it can receive calls from other applications. It has a switch that can be...
