LabVIEW to C++ data-structure conversion.. Documentation please?

[nmalik]

I would like to know how the various structs are converted from LabVIEW objects to their representations in C++. For example, how does a LV String get converted into a LStrHandle? The only thing I know is that I can get how long it is supposed to be, but I don't know how I can interpret this myself. ALSO, I would like documentation on the methods that are available for non-CIN methods, for example NumericArrayResize. It seems that docs for these low level, but important, things is sparce or nonexistant!

And please, no example code. I'm looking for NI documentation or something else with some meat to it.

I appriciate your help!
Naveen

[Greg_McKaskle2]

....
> And please, no example code. I'm looking for NI documentation or
> something else with some meat to it.
>

Inside the LabVIEW directory is a manuals directory that
contains a file called lvexcode.pdf. The pdf is about
300 pages all about DLLs, CINs, exported functions, etc.

I believe there are links to these manuals from the help
files, but I don't have the help in front of me at the
moment.

Greg McKaskle

[nmalik]

Somehow I missed the function descriptions the last time I looked at this pdf. Thanks.

My next question is if there is a better description for the "typeCode" parameter in the NumericArrayResize method. I need to know what values are acceptable and what those values mean. Is it the same as the type definition used in labview?

Naveen

[nmalik]

I've gone through the documentation there and it's lacking in details greatly. The bigest example I have is the typeCode parameter to the NumericArrayResize. I'm guessing that this is the TypeCode as documented in Application Note 154 (LabVIEW Data Storage) but I'm not sure. I'm fairly stuck because I can't use CIN methods to resize an array of strings, but I would like to be able to do this. If I don't get replies to my questions I'll probably try to do it by converting it to arrays of bytes or some other numeric, but that's not the solution I prefer to implement.

Naveen

[Greg_McKaskle2]

> I've gone through the documentation there and it's lacking in details
> greatly. The bigest example I have is the typeCode parameter to the
> NumericArrayResize. I'm guessing that this is the TypeCode as
> documented in Application Note 154 (LabVIEW Data Storage) but I'm not
> sure. I'm fairly stuck because I can't use CIN methods to resize an
> array of strings, but I would like to be able to do this. If I don't
> get replies to my questions I'll probably try to do it by converting
> it to arrays of bytes or some other numeric, but that's not the
> solution I prefer to implement.
>

The typecodes that NumericArrayResize takes is the same as that
listed on page eight in App Note 154. Another way to set the
size is to use SetCINArraySize
. This doesn't require you to know
any typecodes. Note that neither of these functions sets the
dimension sizes of the array.

Greg McKaskle

[nmalik]

Thanks. I've tried using SetCINArraySize but I get linking errors whenever I try. If I add cin.obj to be linked into the dll I'm building I get other linking errors. So, unless you know what these problems could be from I'm restricted in what I can use. NumericArrayResize I can use, so I'll try some more things with that at least.

[Doug (CapeFl)]

The attached link points to numerous details of the low-level parameters of data storage in Labview - it should/could add to your documentation of things-to-know. Good luck with it, Doug

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