The function MPI_Group_excl creates a group of processes newgroup that is obtained by deleting from group those processes with ranks ranks[0], \&... ranks[n-1]. The ordering of processes in newgroup is identical to the ordering in group. Each of the n elements of ranks must be a valid rank in group and all elements must be distinct; otherwise, the call is erroneous. If n = 0, then newgroup is identical to group.
Currently, each of the ranks to exclude must be a valid rank in the group and all elements must be distinct or the function is erroneous. This restriction is per the draft.
Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument. C++ functions do not return errors. If the default error handler is set to MPI::ERRORS_THROW_EXCEPTIONS, then on error the C++ exception mechanism will be used to throw an MPI::Exception object.
called. By default, this error handler aborts the MPI job, except for I/O function errors. The error handler may be changed with MPI_Comm_set_errhandler; the predefined error handler MPI_ERRORS_RETURN may be used to cause error values to be returned. Note that MPI does not guarantee that an MPI program can continue past an error.