How long does it take to access a dll

[NIDave]

Im just curious as to how long it takes LabVIew 7.1 to access a dll via a call library function node. I have done this numerous times and it was always fast before but this time it seems to be alot slower. Im not really blaming LabView since my other ones were fast but I was curious as too how long it takes. Right now I am running an operation in C and it takes 140ms to complete while my LabView call to the same dll takes 285ms. I have timed my LV operations by removing the dll call and leaving all the array and data manipulation and it computes it within 1ms so all the time is spent on or within the dll.

Anyway I just thought this was an interesting topic and maybe someone has the answer.
Thanks, Dave

[Don_Phillips]

Should not take that much longer than the C version actually if any. One thing you can try to do to speed things up on the LabVIEW side (if you have not already done so): When you right click the call library function node and go to "Configure..." on the right side is a pull down to specify if or not the DDLs linked function is threadsafe (reentrant) or not. By default the function is always, I believe, assumed to be non-threadsafe which means it will run in the user interface thread which could be a potential slow down point...

I would only do this if you know that the function is threadsafe, however. If it is it should be configured as such, as this leads to performance improvements.