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Using the USB-845x API Functions in a C/C++ Program

Updated Jan 17, 2023

Reported In


  • USB-8451
  • USB-8452
  • USB-8451 OEM
  • USB-8452 OEM


  • LabWindows/CVI Base

Programming Language

  • C
  • C++

Issue Details

How do I use my USB-845x with a C/C++ Program?


When installing the NI-845x drivers , check that the LabWindows/CVI Support option is checked. Once installed, you can find example programs on calling the NI-845x API from the following directory: Start Menu >> All Programs >> National Instruments >> NI-845x >> Examples.

Similarly, you can find documentation on function definitions in the Documentation folder.


Additional Information

You can find ni845x.dll in the <Windows>\System32 folder (for x64 systems) or the <Windows>\SysWOW64 folder (for x86 systems) in Windows.
The header file, ni845x.h can be found at the following directory: <Program Files(x86)>/National Instruments/Shared/ExternalCompilerSupport/C/include

The SysWOW64 and Program Files (x86) are special folders that only exists on 64-bit Windows and they are intended to store 32-bit binary files.
The System32 and Program Files are folders that exists on 64-bit Windows and they are intended to store 64-bit binary files.