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C/C++, VC6 for UD - Windows

Visual C/C++  examples for the Windows UD library. The Windows UD library is the high-level Windows library/driver for the LabJack U3, U6 and UE9. For other LabJack devices, go to the Software page.

These examples demonstrate static linking (load-time dynamic linking). The UD library dlls are required for the applications to load. To see a few examples using run-time dynamic linking, see the Dev-C examples.

Warning: If you intend to create a 64-bit application please ensure you use AddRequestPtr/eGetPtr/ePutPtr rather than AddRequest/eGet/ePut anywhere you write or read an array of data. See our AddRequest documentation for more information.

Example Packages (old)

UD Library Overview

First read the general overview of the UD library.

The UD driver has a handful of functions, many with the same 4 to 6 parameters.


The main functions are used to build a list of requests (Add), execute the list (Go), and read the result of each request (Get).  Some functions (e.g. eGet) combine a single add/go/get into one function call.


The parameters are described at the bottom of the Overview page.  The meaning of each parameter should be apparent (e.g. Channel is the channel number you are operating on), but when it is not the pseudocode section of the device's datasheet has the extra information needed.

  • Handle:  Always the handle.

  • IOType:  Always the IOType.

  • Channel:  If something besides a channel number the pseudocode section will tell you.

  • Value:  Always the value.

  • X1:  Usually not used, but if used the pseudocode section will tell you.

  • UserData:  Usually not used, but if used the pseudocode section will tell you.


Device specific pseudocode can be found in the device datasheet pseudocode section (U3/U6/UE9).

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