18.2.46. MPI_Comm_compare
MPI_Comm_compare - Compares two communicators.
18.2.46.1. Syntax
18.2.46.1.1. C Syntax
#include <mpi.h>
int MPI_Comm_compare(MPI_Comm comm1, MPI_Comm comm2, int *result)
18.2.46.1.2. Fortran Syntax
USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_COMM_COMPARE(COMM1, COMM2, RESULT, IERROR)
INTEGER COMM1, COMM2, RESULT, IERROR
18.2.46.1.3. Fortran 2008 Syntax
USE mpi_f08
MPI_Comm_compare(comm1, comm2, result, ierror)
TYPE(MPI_Comm), INTENT(IN) :: comm1, comm2
INTEGER, INTENT(OUT) :: result
INTEGER, OPTIONAL, INTENT(OUT) :: ierror
18.2.46.2. Input Parameters
comm1
: Comm1 (handle).comm2
: Comm2 (handle).
18.2.46.3. Output Parameters
result
: Result of comparison (integer).IERROR
: Fortran only: Error status (integer).
18.2.46.4. Description
MPI_IDENT result
s if and only if comm1
and comm2
are
handles for the same object (identical groups and same contexts).
MPI_CONGRUENT results if the underlying groups are identical in
constituents and rank order; these communicators differ only by context.
MPI_SIMILAR results of the group members of both communicators are
the same but the rank order differs. MPI_UNEQUAL results otherwise.
18.2.46.5. 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.