Synopsis

int MPIX_Type_iov(MPI_Datatype datatype, MPI_Count iov_offset, MPIX_Iov *iov,
                  MPI_Count max_iov_len, MPI_Count *actual_iov_len)

Input Parameters

datatype

datatype (handle)

iov_offset

number of contiguous segments to skip (integer)

max_iov_len

capacity for the segments array (integer)

Output Parameters

iov

contiguous segments array for output (None)

actual_iov_len

actual number of segments in output (integer)

MPIX Function

This routine is part of the MPIX extension to the MPI standard. It may become part of the standard in the future, in which its signature will change to the MPI prefix.

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 guarantee 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.

  • MPI_ERR_ARG - Invalid argument. Some argument is invalid and is not identified by a specific error class (e.g., 'MPI_ERR_RANK').

  • MPI_ERR_TYPE - Invalid datatype argument. Additionally, this error can occur if an uncommitted MPI_Datatype (see 'MPI_Type_commit') is used in a communication call.

  • MPI_ERR_OTHER - Other error; use 'MPI_Error_string' to get more information about this error code.