MPI_Comm_create_keyval - Create a new attribute key
int MPI_Comm_create_keyval(MPI_Comm_copy_attr_function *comm_copy_attr_fn,
int *comm_keyval, void *extra_state)
- - Copy callback function for keyval
- - Delete callback function for keyval
- - Extra state for callback functions
- - key value for future access (integer)
Key values are global (available for any and all communicators).
Default copy and delete functions are available. These are
- - empty copy function
- - empty delete function
- - simple dup function
There are subtle differences between C and Fortran that require that the
copy_fn be written in the same language from which
MPI_Comm_create_keyval is called. This should not be a problem for
most users; only programmers using both Fortran and C in the same program
need to be sure that they follow this rule.
The MPI-2 versions of the attribute callbacks should return either
on success or a valid MPI error code or class on failure.
The MPI standard is ambiguous on this point, but as MPI-2 provides the
the user to define and use MPI error codes and classes.
This routine is thread-safe. This means that this routine may be safely used by
multiple threads without the need for any user-provided thread locks. However,
the routine is not interrupt safe. Typically, this is due to the use of memory
allocation routines such as malloc
or other non-MPICH runtime routines
that are themselves not interrupt-safe.
All MPI routines in Fortran (except for MPI_WTIME
have an additional argument ierr
at the end of the argument list.
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
All MPI objects (e.g., MPI_Datatype
) are of type
All MPI routines (except MPI_Wtime
) 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_Comm_set_errhandler
(for files), and MPI_Win_set_errhandler
(for RMA windows). The MPI-1 routine MPI_Errhandler_set
may be used but
its use is deprecated. The predefined error handler MPI_ERRORS_RETURN
may be used to cause error values to be returned. Note that MPI does
guarentee that an MPI program can continue past an error; however,
MPI implementations will attempt to continue whenever possible.
- - No error; MPI routine completed successfully.