LabVIEW
Memory leak and problem with polymorh vi when calling vi from dll
Two problems appear for me when using the setup below.
First, I have a vi for opening a secondary vi:
Then I have a vi for calling the opened, secondary vi:
These two are compiled to a dll. The first one is called once, calling a function "open(char *)". The second one is called over and over, calling a function nextevent(double *, int). A simple example of an opened, secondary vi looks like this:
The code used to send data looks approximately like this:
dataout = malloc(dx->numelems * sizeof(double));
datain = (COMPLEX *) dx->cont;
for (i = 0; i < dx->numelems; ++i)
{
dataout[cnt][i] = sqrt(datain[i].re * datain[i].re + datain[i].im * datain[i].im);
}
nextevent(dataout, dx->numelems);
free(dataout);
This code is called in a loop. dataout is a double array to be sent to the secondary vi, datain is the source data.
The problem now is that there is something eating up memory, and I fail to see why.
My second question is this:
I want to insert a Hamming window, or some other form of windowing function. It doesn't work however, and the help tells me it is because a vi opened this way cannot contain any polymorphic vi. Is there a convenient way around this problem?
Regarding your second question:
As you say not possible to use a polymorphic vi in a DLL and in your case it is the windowing VI that is polymorphic. What you can do is to use only one instance of the windowing VI in the short cut menu.
Here is a link to a report about this error in the knowledgeBase:
http://digital.ni.com/public.nsf/allkb/755CE99505A1C9FF8625693C00508DDE?OpenDocument
