Hello, I know, using stdout and stderr within MPI programs is in no way good. Nevertheless I found that - and now wonder why - isatty inside an MPI program reports different values for stdout and stderr in Open MPI:
# Running as non MPI program: ./isatty-test [0/1] stdout FILENO: 1, TTY: 1 [0/1] stderr FILENO: 2, TTY: 1 # Running with Open MPI 1.8.7: mpirun -np 2 ./isatty-test [1/2] stdout FILENO: 1, TTY: 1 [1/2] stderr FILENO: 2, TTY: 0 [0/2] stdout FILENO: 1, TTY: 1 [0/2] stderr FILENO: 2, TTY: 0 ... not sure if this is good or bad. Both are forwarded correctly to the tty as far as I see... Redirecting stdout or stderr to files does not change anything in the Open MPI case. Best regards Christoph Niethammer PS: MPICH reports in all cases 0 for isatty() on stdout and stderr.
