TestStand and LabWindows DLL's Sharing Data

[donahut]

What is the best method of sharing a "C" structure used by several DLL's (built in LabWindows/CVI) that are called by several Test Stand Step's (CVI Adapter)? Do you have to use TestStand API calls or can the data be shared somehow (dllimport/dllexport,ActiveXserver)? Can these variables also be visible to Test Stand ?

[David Mc]

Hi donahut,

The method we recommend for sharing data between code modules (C/C++ DLLs, LabVIEW VIs, etc) called by successive TestStand is to store the data in TestStand local variables, and pass those as input or output parameters to the various code modules. These local variables are also completely available in TestStand as well, so TestStand can read these values or modify them if necessary.

A C struct is represented in TestStand as "container" datatype. An example of passing structs between TestStand and a C DLL ships with TestStand and is located in \Examples\StructPassing\C (if you have installed the TestStand examples).

Thanks for contacting National Instruments!
David Mc.
NI Application Engineer