NAME

       MPI_Group_size - Returns the size of a group.

SYNTAX

C Syntax

       #include <mpi.h>
       int MPI_Group_size(MPI_Group group, int *size)

Fortran Syntax

       INCLUDE 'mpif.h'
       MPI_GROUP_SIZE(GROUP, SIZE, IERROR)
            INTEGER   GROUP, SIZE, IERROR

C++ Syntax

       #include <mpi.h>
       int Group::Get_size() const

INPUT PARAMETERS

       group     Group (handle).

OUTPUT PARAMETERS

       size      Number of processes in the group (integer).

       IERROR    Fortran only: Error status (integer).

DESCRIPTION

       MPI_Group_size  returns  in  size the number of processes in the group. Thus, if group = MPI_GROUP_EMPTY,
       then the call will return size = 0. On the other hand, a call with group = MPI_GROUP_NULL is erroneous.

ERRORS

       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.

       Before  the  error  value  is  returned,  the current MPI error handler is 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.