Hi Edin, I think you won't get any concurrency from using netCDF in multiple threads, even if netCDF-4 was thread-safe, because the underlying HDF5 library just serializes all the calls with locks for thread safety, so it doesn't support concurrent access to a single HDF5 file by multiple threads: http://www.hdfgroup.uiuc.edu/papers/features/mthdf/ > For your reference I have attached my Read_CDF.c file Sorry, but we didn't get the attachment. Is it possible you forgot to attach it? But perhaps the above comment on thread safety answers your question so that we wouldn't need to look at the attachment. --Russ Russ Rew UCAR Unidata Program address@hidden http://www.unidata.ucar.edu Ticket Details =================== Ticket ID: WTN-189414 Department: Support netCDF Priority: Normal Status: Closed