NI DAQmxBase OpenSUSE Dynmaic Load of libnidaqmxbase.so not Working Correctly

Question

I am trying to use NI DAQmxBase 14.0 on OpenSUSE 13.1 via a C++ class that dynamically loads the shared library (libnidaqmxbase.so) at runtime and maps the various calls that I need including CreateAIVoltageChannel, The reason for doing this is that sometime the code will run on a machine with the drivers and libraries installed and sometimes not.
When I test this with a machine that has the drivers installed but no NI card in I get random results depending on how the program is linked.The program is a simple console app that calls getDevSerialNum on device names.
If the program is linked with the shared library (using -lnidaqmxbase) then the program runs successfully. If the program is linked without the shared library (no other code changes) the program runs but does not correctly return the device serial call (it should return an error but does not).
My assumption is that there is some special initialisation code that should be called to correctly initialise the library. Any ideas?
 

Answer 1

SimonSparkes wrote:
I am trying to use NI DAQmxBase 14.0 on OpenSUSE 13.1 via a C++ class that dynamically loads the shared library (libnidaqmxbase.so) at runtime and maps the various calls that I need including CreateAIVoltageChannel, The reason for doing this is that sometime the code will run on a machine with the drivers and libraries installed and sometimes not.
When I test this with a machine that has the drivers installed but no NI card in I get random results depending on how the program is linked. The program is a simple console app that calls getDevSerialNum on device names.
If the program is linked with the shared library (using -lnidaqmxbase) then the program runs successfully. If the program is linked without the shared library (no other code changes) the program runs but does not correctly return the device serial call (it should return an error but does not).
My assumption is that there is some special initialisation code that should be called to correctly initialise the library. Any ideas?
Hi Simon,
This is a known bug in the LabVIEW 2012 Run-Time Engine, upon which the DAQmx Base 14.0 C API is built.
If you add LD_DEBUG=all to your environment before running your executable, you'll see why. In short, the LabVIEW Run-Time Engine's shared objects don't fully advertise all of their dependencies, which causes ld to fail finding all of the symbols.
The workaround is to create an intermediate wrapper library that uses -lnidaqmsbase when built and only using dlopen to load it on systems that have the driver installed.
My team has been working on a fix with LabVIEW, and if you're interested in joining the DAQmx Base 2015 Beta Program, please send me a direct message with your email address.