Can multiple Write to Spreadsheet VIs cause one change to be overwritten?

[RNLK]

In my program right now I'm running two parallel loops, both of which have a Write to Spreadsheet VI writing to the same file path.  I don't really care which order the lines are added to the spreadsheet, as the data from the two different loops can be differentiated, but what I am wondering is whether it is possible for the two VIs to run simultaneously and have one change overwrite the other so there would be a missing line in the final result.  I've seen that this is a risk for writing to local variables in parallel loops, but haven't seen anything either way specifically for writing to an exterior file.

Thanks for your help.

[crossrulz · Accepted solution]

The Write to Spreadsheet File is non-reentrant, so only one instance of it can run at a time.  As long as you are always concatinating, I wouldn't expect any loss of data.

However, a better solution would be to have another loop to handle your File IO.  Then you can open the file and keep it open.  You send data to be written using a queue.  And remember to close the file on exit.