read.csv/write.csv Synchronization in R
===

I have multiple instances of a code running on bunch of projects. The list of projects are included in projList.csv. When an R instance picks up a  project it writes 1 in front of the project name in the projList.csv to prevent the other instances to redo what has already been done. 

I want to avoid the following synchronization problems:
- I do not want to allow reading the list file while another process is writing on it.
- I do not want to allow writing when another process is wither writing on it or reading it. 

Is there anyway to do that?

Thanks
