Re : Call DLL function with pointer to complex structure

[NewCLAD]

Hello,

I try to call a function using CLFN. My problem is the parameters of the function I try to access.

Here is the function and his parameters:

typedef struct _BAR_INFO
{
    ULONG              dwSize;    
    ULONG              dwFlag;
}BAR_INFO, PBAR_INFO;

typedef struct _DEVICE_INFO
{
    ULONG              dwBarNum;
    BAR_INFO           BarInfo[6];
}DEVICE_INFO, *PDEVICE_INFO;

DLLIMPORT int GetDeviceInfo(
    unsigned int      devID,
    PDEVICE_INFO      pdevinfo
)
{
    ULONG             i;
  
    if(devID >= DevNum)
        return PCICORE_DEVICE_NO_FOUND;
    
    if(DevTable[devID].DevHandle == NULL)
        return PCICORE_DEVICE_NO_INITIALIZE;

    if(pdevinfo == NULL)
        return PCICORE_INVALID_PARAMETER;
   
    pdevinfo->dwBarNum = DevTable[devID].DevInfo.dwBarNum;
    for(i = 0; i < pdevinfo->dwBarNum; i++)
    {
        pdevinfo->BarInfo[i].dwFlag = 
            DevTable[devID].DevInfo.BarInfo[i].dwFlag;
        pdevinfo->BarInfo[i].dwSize = 
            DevTable[devID].DevInfo.BarInfo[i].dwSize;
    }

    return PCICORE_SUCCESS;
}

 In attached file there is the Get Device Info.vi that try to access this function. The code crashes when the function is called.

I probably don't pass the data parameters correctly to the CLFN.

Thanks for your lights §

[NewCLAD]

The VI attached

[nathand · Accepted solution]

A fixed-size array in C is equivalent to a LabVIEW cluster containing  the same number of identical elements, so you need to replace the array with a cluster. Also, structs are always passed by reference and the C function expects a pointer to a struct, so you don't need to unbundle. Pass the cluster directly to the function as a single parameter. Try the attached revised version of your VI.

[NewCLAD]

Thanks Nathan. Its working fine.