NAME

       MPI_Comm_delete_attr - Deletes attribute value associated with a key.

SYNTAX

C Syntax

       #include <mpi.h>
       int MPI_Comm_delete_attr(MPI_Comm comm, int comm_keyval)

Fortran Syntax

       USE MPI
       ! or the older form: INCLUDE 'mpif.h'
       MPI_COMM_DELETE_ATTR(COMM, COMM_KEYVAL, IERROR)
            INTEGER   COMM, COMM_KEYVAL, IERROR

Fortran 2008 Syntax

       USE mpi_f08
       MPI_Comm_delete_attr(comm, comm_keyval, ierror)
            TYPE(MPI_Comm), INTENT(IN) :: comm
            INTEGER, INTENT(IN) :: comm_keyval
            INTEGER, OPTIONAL, INTENT(OUT) :: ierror

C++ Syntax

       #include <mpi.h>
       void MPI::Comm::Delete_attr(int comm_keyval)

INPUT/OUTPUT PARAMETER

       comm      Communicator from which the attribute is deleted (handle).

INPUT PARAMETER

       comm_keyval
                 Key value (integer).

OUTPUT PARAMETER

       IERROR    Fortran only: Error status (integer).

DESCRIPTION

       MPI_Comm_delete_attr  deletes  an  attribute  from cache by key. This function invokes the
       attribute delete function delete_fn specified when the comm_keyval was created.  The  call
       will fail if the delete_fn function returns an error code other than MPI_SUCCESS.

       Whenever  a  communicator is replicated using the function MPI_Comm_dup, all callback copy
       functions for attributes that are currently set are invoked (in arbitrary order). Whenever
       a  communicator is deleted using the function MPI_Comm_free, all callback delete functions
       for attributes that are currently set are invoked.

       This function is the same as MPI_Attr_delete but is  needed  to  match  the  communicator-
       specific  functions  introduced  in  the  MPI-2  standard.  The  use of MPI_Attr_delete is
       deprecated.

NOTES

       Note that it is not defined by the MPI standard what happens  if  the  delete_fn  callback
       invokes other MPI functions.  In Open MPI, it is not valid for delete_fn callbacks (or any
       of their children) to add or delete attributes on the same object on which  the  delete_fn
       callback is being invoked.

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.