c++ builder 6 unresolved external error loading a dll

[slapierre]

Im using LabVIEW 6.1 and i'm trying to export a DLL that performs math routines (such as FFT and stuff..) to include it im my BC#B6 project. I chose the C Calling convention (because the Standard Calling Convention cannot be converted by the Coff2omf.exe tool (to get rid of the 0x21 error)). Still, i now get the following linking error (it searches for an underscore before the first letter of my function):

[Linker Error] Unresolved external '_calcul' referenced from E:\WORK\PROJECT\CALLINGFORM.OBJ

for now i only have a simple "multiply by 2" function that takes an int and returns an int :
int16 __cdecl calcul(int16 Input);

I would like to know...
1 - How to get rid of this problem - where is the source
of the problem (application builder i guess)?
2 - Will I have this problem if i link dynamically the driver?
3 - do i need to link the Run-time engine dlls to make it work in both static and dynamic loading?

Simon Lapierre
slapierre@sonomax.com

[KKenM]

Hi,
It may be that the linker is looking definitions(libraries) of the functions you are using. Make sure the linker can resolve the paths to any "external" functions, for example, C math routine functions.
'Ope this helps,
-ken-

[Sean_C.]

Hello Simon,

Thank you for contacting National Instruments.

When you created your DLL in LabVIEW, a LIB file should also have been created. To call the DLL in C#, make sure that you include the LIB file in C#.

In answer to your questions:

1. You can solve this problem by including the LIB file in C#.
2. You will not have this problem if you dynamically link the driver.
3. You do not need to link the Run-time engine DLLs to make it work in both static and dynamic loading.

I hope this helps. Let me know if this does not solve your problem.

Sean C.
Applications Engineer
National Instruments

[KKenM]

Sean,
Since Simon is trying to link an existing DLL using the Labview code node, the library that should be available in the same location, or in a resolvable path is the .LIB file that was prouduced by the C compiler
Thus, if he is linking xxxx.DLL he should also have xxxx.LIB ( his math fuction definitions) I hope this
is a bit clearer than my earlier post
Ken