Hello everyone I am working on a DLL invocation which needs to resize and fill an array of doubles named 'values' (2nd to last parameter). I have defined the signature as follows: _declspec (dllexport) uint8_t readDoubleArray(uint8_t handle, LStrHandle lPath, int64_t startTime, int64_t endTime, DblArrHdl *values, LongArrHdl *timebase);Where DblArrHdl is typedef struct { int32_t dimSize; double doubles[1]; } DblArr; typedef DblArr **DblArrHdl; In the invocation I read doubles from a database, and resize the double array as follows: int size = doubleArray.size(); if (NumericArrayResize(0x0A, 1, (UHandle*)values, size) != noErr) { setLastError(MG_ERR_LABVIEW_ERROR, "Failed to allocate memory"); return FALSE; } I set the size, and copy the values: (**values)->dimSize = size;for (int i = 0; i < size; i++) { (**values)->doubles[i] = doubleArray[i];}When I use the DbgPrintF to validate the values it gives me a value around 120000 which is correct. However, when returned by labview the array contains strange data, like 5.38564E-315. Here is print out of the 'values' array after it has been through the DLL: Here is how I wired it, ignore the clustering, it occurs in the array of values which exits the DLL call. I have no idea how this can be. I followed the examples on the site. I also tried the normal DSSetHandleSize, but it didn't change anything. Any idea what I did wrong?Thanks in advance,Vincent Message Edited by DaVince on 10-22-2008 10:10 AM

Hi again, Vincent, you have problem with alignment. Just add #pragma pack (1) before array declaration:#pragma pack (1)typedef struct { int32 dimSize; float64 elt[1]; } TD2;typedef TD2 **TD2Hdl;and all should be OK. See example in attachment. Andrey.

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LabVIEW

Array of doubles filled by DLL contains weird values

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Thanks for the resources! I'm quite new to C++ too (was more Java developer)... I forgot about that the compiler aligns datatypes :S oops. But its a very educational experience 🙂 I'm interfacing our remote database in the DLL, which uses ZeroC ICE, so native LabView was not possible. As an alternative I could talk ICE protocol directly over LabView sockets... but lets not go there 🙂

Again, thanks for your help.

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LabVIEW

Array of doubles filled by DLL contains weird values

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