Calling Shared Library

[e.cote]

I hope Someone can help me because I've been struggling with that for at lease 2 weeks.

I'm using LabVIEW linux with CentOS 7. trying to access and USB-1408FS-Plus (DAQ) from Measurement computing.

I've got the ".so" and ".h" header files but when I try to use the wizard for building the functions it doesn't quite work. So I just thought of making the function manually by entering the parameters.

The function in C is:

 UlError ulGetDaqDeviceInventory(DaqDeviceInterface interfaceTypes, DaqDeviceDescriptor daqDevDescriptors[], unsigned int* numDescriptors)

UlError is an ENUM

InterfaceTypes is an ENUM

DaqDeviceDescriptor is a type:

struct DaqDeviceDescriptor

{

char productName[64];

unsigned int productId;

DaqDeviceInterface devInterface;

char devString[64];

char uniqueId[64];

char reserved[512];.

};

typedef struct DaqDeviceDescriptor DaqDeviceDescriptor;

so I decided to create in LabVIEW a cluster that included an byte Array (ProductName), a U32 integer for ProductID  and so on

 but I think it doesn't like that from I a read on the web shared library doesn't like passing a structure type if it contains an array.

some seemed to say that I need to replace my array of byte by a pointer. How do I do that?

any idea?

Thanks in advance

[nathand]

You need to replace the fixed-length arrays with LabVIEW clusters containing the same number of elements of the correct type. So, if you have a cluster representing a DaqDeviceDescriptor, it should contain as elements:

a cluster of 64 U8 for productName

a U32 (probably) for productId

a cluster of 64 U8 for devString

a cluster of 64 U8 for uniqueId

and something containing 512 bytes for reserved. I think the maximum number of elements in a cluster is 256, and anyway large clusters are unwieldy, so probably easier to make that a cluster containing 64 U64 elements.

Alternatively, you can create an array of 64 + 4 + 64 + 64 + 512 = 708 bytes and pass that, then parse out the portions you want afterwards.

If you need more assistance, please attach:

- screenshots or snippets of your code, so we can see what's happening without loading LabVIEW (or in case we're working in an older version than you are)

- your actual code, if you don't provide a snippet

- documentation on the functions you're trying to call and the data types you're using