17.2.194. MPI_Group_size
MPI_Group_size - Returns the size of a group.
17.2.194.1. SYNTAX
17.2.194.1.1. C Syntax
#include <mpi.h>
int MPI_Group_size(MPI_Group group, int *size)
17.2.194.1.2. Fortran Syntax
USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_GROUP_SIZE(GROUP, SIZE, IERROR)
INTEGER GROUP, SIZE, IERROR
17.2.194.1.3. Fortran 2008 Syntax
USE mpi_f08
MPI_Group_size(group, size, ierror)
TYPE(MPI_Group), INTENT(IN) :: group
INTEGER, INTENT(OUT) :: size
INTEGER, OPTIONAL, INTENT(OUT) :: ierror
17.2.194.2. INPUT PARAMETERS
group
: Group (handle).
17.2.194.3. OUTPUT PARAMETERS
size
: Number of processes in the group (integer).IERROR
: Fortran only: Error status (integer).
17.2.194.4. 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.
17.2.194.5. ERRORS
Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument.
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.