LabWindows/CVI

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Product DocumentationLabWindows/CVIActiveX Library OverviewCurrent page
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ActiveX Library Overview

ActiveX Library Overview

This section describes the ActiveX Library. The Building ActiveX Servers in LabWindows/CVI book contains conceptual information about ActiveX Automation as well as guidelines for using the ActiveX Library. To access information about each function, you can use the function tree list of ActiveX Library functions or click the function name in the Library Reference»ActiveX Library»Alphabetical List of Functions section of this help file.

(Linux) The functions in the ActiveX Library are not supported.

The ActiveX Library contains functions that facilitate calling into ActiveX server interfaces. These functions are intended to be used in conjunction with the ActiveX controller instrument drivers that the Create ActiveX Controller Wizard generates, and with ActiveX server code that the Create ActiveX Server Wizard generates. The ActiveX controller instrument drivers contain functions that create ActiveX objects, call ActiveX object methods, and get and set ActiveX object properties. Select Tools»Create ActiveX Controller to launch the ActiveX Controller Wizard. Select Tools»Create ActiveX Server to launch the ActiveX Server Wizard.

The ActiveX Library contains functions that perform the following actions:

  • Help you work with the VARIANT parameters, SAFEARRAY parameters, and return values of the functions in the generated instrument drivers.
  • Free resources dynamically allocated by generated instrument drivers or by other ActiveX Library functions.
  • Display error information returned by ActiveX Library functions or ActiveX server methods.

The ActiveX Library also contains low-level functions that the generated drivers use. These low-level functions invoke server object methods and get and set server object properties.

If you want to use the low-level functions, familiarize yourself with ActiveX concepts. In particular, know how to browse through an ActiveX server type library.

Some ActiveX server objects generate events in addition to providing methods for you to call from an ActiveX client program. The ActiveX controller instrument drivers contain callback registration functions that allow you to specify a callback that is called when the server generates a specific event. The prototype of the event callback that you must create depends on the definition of the event. When you register a callback, you must specify a particular server object from which you want to receive the event. The function panel help for each event's callback registration function specifies which server objects generate which events.

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