http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47618
--- Comment #11 from Roland Schulz <roland at rschulz dot eu> 2012-07-25 00:50:30 UTC --- Steven wrote that they are not merged but that race conditions occur. That is also what I observed. To clarify: Message Passing Interface (MPI) is a parallelization method which executes the same binary multiple times in parallel (with support for messages for communication). Allowing to merge the output into one file at runtime would require file-locking (often over network file-systems) and would not scale because MPI applications are often used with more than >10000 (or even >1M) parallel processes simultaneous.
