What Is LabWindows/CVI? The C Environment for Test and Measurement

LabWindows/CVI is National Instruments' ANSI C development environment for test and measurement. If LabVIEW is the graphical option, LabWindows CVI is the text-based C option for the same job: data acquisition, instrument control, and automated test. Engineers who prefer writing code over wiring diagrams often land here.

What LabWindows/CVI is

NI LabWindows is a full C IDE tuned for test and measurement:

• •Write applications in standard ANSI C.
• •Use built-in libraries for DAQ, instrument I/O (VISA/GPIB), analysis, and user interfaces.
• •Build operator GUIs with a UI editor.
• •Integrate with NI hardware and drivers.

It appeals to teams with C expertise, or those integrating test code with existing C/C++ systems.

LabWindows/CVI vs LabVIEW

Both are NI products, so both carry subscription cost and NI ecosystem lock-in. The choice between them is mostly about whether your team prefers text or graphical programming. See what LabVIEW is for the other side.

Modern alternatives

If you want to write code for test but not be locked into NI's C environment:

• •Python has become the default for new test code, with pyVISA and nidaqmx. See LabVIEW vs Python and DAQ with Python.
• •TestFlow generates instrument scripts and validation plans with AI, so you write far less low-level code at all.

Where TestFlow fits

LabWindows/CVI exists because some engineers want the control of writing code. TestFlow keeps that control while removing the boilerplate: AI drafts the scripts and plans, using a vendor-agnostic layer, and you refine them. For C-based test teams looking to cut maintenance and avoid NI lock-in, the free version is a quick comparison.

Frequently asked questions

What is LabWindows/CVI used for? Building test and measurement applications in ANSI C, including DAQ, instrument control, and automated test.

Is LabWindows/CVI the same as LabVIEW? No. LabWindows/CVI uses text-based C; LabVIEW uses graphical G. Both are NI products for similar tasks.

Is LabWindows/CVI still supported? It remains an NI product, though new test development has largely shifted toward Python and other modern tooling.