Tbb.dll entrypoint not found

Question

Hello,
I have moved a DLL dependant sourcecode with all it´s DLLs but functions from the top DL library fail to load;
When I select the function click OK, I get an dialog saying that tbb.dll some procedure entrypoint was not found. This is probably caused by loading different dll by labview or the calling dll.
The top library is using vision.h and there are calls to opencv functions, that probably use some different version of tbb.dll.
I tried to recompile and rebuild the used DLL in MSVS on the target computer with no problems, but the problem still persists.

Answer 1

tbb.dll (and it's accompagning DLLs) is a DLL that gets normally installed in the system32 directory. As such you should avoid to have it anywhere else on your system. Now it seems tbb gets actually installed by several LabVIEW components and so is already loaded in recent LabVIEW versions when LabVIEW gets started.
Now you might get in a number of troubles here. First if you reference the DLL by path in a Call Library Node Windows will load the DLL as so called SxS (Side by Side) DLL into memory. This is to prevent troubles with different components expecting different versions of the DLL, yet it opens up a big can of worms too. Most DLLs getting installed in system32 do so because they maintain global state and other things internally that gets totally messed up when you load the DLL again from a different location.
Another problem however can be version differences in the DLL. The standard version installed by whatever software makes use of it, may be older than what your own software needs. In that case you have to install the newer version of the library in your system to replace the older version, not put it somewhere else to be loaded in parallel. And keep your fingers crossed, that the library has not introduced incompatible chances between versions, as that would simply make whatever other software has used it before, fail now. Yes it's all DLL hell, but SxS would not be the solution for it either, just a different way of getting roasted in DLL hell.
Rolf Kalbermatter
CIT Engineering Netherlands
a division of Test & Measurement Solutions