Currently the gfortran IO library is supposed to be thread safe. Additionally, allowing multiple processes to access the same file could be useful, and if we eventually want to support co-arrays with multiple processes, it will be needed as co-arrays specify that multiple images can access a single file.
On POSIX this can be accomplished with the fcntl() syscall. We'd certainly want to make this optional (perhaps with a compiler command-line switch like the fpe options), to avoid the fcntl() overhead as well as frequent buffer flushing in normal single-process usage. -- Summary: [libgfortran] Optionally support multi-process locking Product: gcc Version: 4.2.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: libfortran AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: jb at gcc dot gnu dot org OtherBugsDependingO 18918,25561 nThis: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25830