bionic (3) MPI_Comm_create_keyval.3.gz

NAME

       MPI_Comm_create_keyval -  Create a new attribute key

SYNOPSIS

       int MPI_Comm_create_keyval(MPI_Comm_copy_attr_function *comm_copy_attr_fn,
                                MPI_Comm_delete_attr_function *comm_delete_attr_fn,
                                int *comm_keyval, void *extra_state)

INPUT PARAMETERS

       comm_copy_attr_fn
              - Copy callback function for keyval

       comm_delete_attr_fn
              - Delete callback function for keyval

       extra_state
              - Extra state for callback functions

OUTPUT PARAMETERS

       comm_keyval
              - key value for future access (integer)

NOTES

       Key values are global (available for any and all communicators).

       Default copy and delete functions are available.  These are
       MPI_COMM_NULL_COPY_FN
              - empty copy function
       MPI_COMM_NULL_DELETE_FN
              - empty delete function
       MPI_COMM_DUP_FN
              - 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.

RETURN VALUE FROM ATTRIBUTE CALLBACKS

       The MPI-2 versions of the attribute callbacks should return either MPI_SUCCESS 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
       routines MPI_Add_error_class and MPI_Add_error_code that allow the user to define and use MPI error codes
       and classes.

THREAD AND INTERRUPT SAFETY

       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.

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_Comm_set_errhandler   (for   communicators),   MPI_File_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 not guarentee that an MPI program can continue past an error; however,  MPI
       implementations will attempt to continue whenever possible.

       MPI_SUCCESS
              - No error; MPI routine completed successfully.

SEE ALSO

       MPI_Comm_free_keyval

                                                   11/12/2016                          MPI_Comm_create_keyval(3)