MPI_Comm_free(3)

NAME
MPI_Comm_free - Marks the communicator object for deallocation

SYNOPSIS
#include "mpi.h"
int MPI_Comm_free ( MPI_Comm *commp )

INPUT PARAMETER
comm
    - communicator to be destroyed (handle)

NULL HANDLES
The MPI 1.1 specification, in the section on opaque objects, explicitly

DISALLOWS FREEING A NULL COMMUNICATOR. THE TEXT FROM THE STANDARD IS
A null handle argument is an erroneous IN argument in MPI calls, unless an
exception is explicitly stated in the text that defines the function. Such
exception is allowed for handles to request objects in Wait and Test calls
(sections Communication Completion and Multiple Completions ). Otherwise, a
null handle can only be passed to a function that allocates a new object and
returns a reference to it in the handle.

NOTES FOR FORTRAN
All MPI routines in Fortran (except for MPI_WTIME and MPI_WTICK ) have an additional argument ierr at the end of the argument list. ierr is an integer and has the same meaning as the return value of the routine in C. In Fortran, MPI routines are subroutines, and are invoked with the call statement. All MPI objects (e.g., MPI_Datatype , MPI_Comm ) are of type INTEGER in Fortran.

ERRORS
All MPI routines (except MPI_Wtime and MPI_Wtick ) return an error value; C routines as the value of the function and Fortran routines in the last argument. Before the value is returned, the current MPI error handler is called. By default, this error handler aborts the MPI job. The error handler may be changed with MPI_Errhandler_set ; the predefined error handler MPI_ERRORS_RETURN may be used to cause error values to be returned. Note that MPI does not guarentee that an MPI program can continue past an error.
MPI_SUCCESS
    - No error; MPI routine completed successfully.
MPI_ERR_COMM
    - Invalid communicator. A common error is to use a null communicator in a call (not even allowed in MPI_Comm_rank ).
MPI_ERR_ARG
    - Invalid argument. Some argument is invalid and is not identified by a specific error class (e.g., MPI_ERR_RANK ).

LOCATION
comm_free.c