Trouble using global variable for file reference

[j_osh_o]

Hi all,

This code is trivial but illustrates the problem I am having.  I want to open a file with vi A, dynamically open vi B, pass the file reference to vi B, close vi B, then close the fiel with vi A.  vi B is designed to continuously sample data and add it to the file.  Unfortunately I can't implement this solution because it appears that global variables do not work for file references(!).  Thanks!

[j_osh_o]

Additional comment: the attached code fails because of invalide file reference.  If the global variables are removed and the wire is connected directly, the code works fine.

[RavensFan · Accepted solution]

You have a race condition in that picture.  The global variable refnum out could be read at the File write before the File Open has had a chance to write a valid file reference to the other global variable refnum copy.  You should have a wire from the Open to the write directly.  If you want to store it in the global variable as well, then branch it off that direct wire.