NAME

       MPI_Comm_free  - Mark a communicator object for deallocation.

SYNTAX

C Syntax

       #include <mpi.h>
       int MPI_Comm_free(MPI_Comm *comm)

Fortran Syntax

       INCLUDE 'mpif.h'
       MPI_COMM_FREE(COMM, IERROR)
            INTEGER   COMM, IERROR

C++ Syntax

       #include <mpi.h>
       void Comm::Free()

INPUT PARAMETER

       comm      Communicator to be destroyed (handle).

OUTPUT PARAMETER

       IERROR    Fortran only: Error status (integer).

DESCRIPTION

       This  operation  marks  the  communicator  object  for  deallocation. The handle is set to
       MPI_COMM_NULL. Any pending operations that use this communicator will  complete  normally;
       the  object  is  actually  deallocated only if there are no other active references to it.
       This call applies to intracommunicators and intercommunicators. Upon actual  deallocation,
       the  delete  callback  functions  for  all cached attributes (see Section 5.7 in the MPI-1
       Standard, "Caching") are called in arbitrary order.

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.