Call library function- memory allocation

[ToeCutter]

Hi,

I want to call a dll from LabVIEW and one of the inputs expects a pointer to double (double*). I have done things like this before and use create array to allocate the memory in LabVIEW to pass to the dll. This time what is expected is a pointer to a single double. Can I just wire a diagram numeric double to the input or will this not actually allocate memory?

[nathand · Accepted solution]

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ToeCutter wrote:

I want to call a dll from LabVIEW and one of the inputs expects a pointer to double (double*). I have done things like this before and use create array to allocate the memory in LabVIEW to pass to the dll. This time what is expected is a pointer to a single double. Can I just wire a diagram numeric double to the input or will this not actually allocate memory?

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It would be better to wire a single instead of a double, but other than that(oops, misread "single double" as "single"), yes, it will correctly allocate memory. You just need to configure the parameter as a single double passed by pointer.

[ToeCutter]

Thanks, but why would I pass a single when the function expects a double??

[edit]I see the confusion now- by 'single double' I mean the function expects a pointer that points to exactly one instance of a double, rather than the first element of an array.

[nathand]

Oh, sorry, misread "pointer to a single double" as "pointer to a single." Ignore that part of my comment and wire in a double.