FileLocked or FileInUse

[zanz]

Searching these forums, I've haven't gotten a clear answer to this question:

How or what's the best way to detect a file that's locked by Windows or in use by another process?

Is there anything equivalent to IsFileLocked? or IsFileInUse in NSIS? that would return true or false depending if the file is locked or not? Any plugins (I couldn't find a built in function in the documentation either).

If there are no docs or plug-ins, then any guidance would be really appreciated on how i can get status of a file before uninstalling or upgrading the product.

Thanks!