17.2.457. MPI_Win_start

MPI_Win_start - Starts an RMA access epoch for win

17.2.457.1. SYNTAX

17.2.457.1.1. C Syntax

#include <mpi.h>

int MPI_Win_start(MPI_Group group, int assert, MPI_Win win)

17.2.457.1.2. Fortran Syntax

USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_WIN_START(GROUP, ASSERT, WIN, IERROR)
     INTEGER GROUP, ASSERT, WIN, IERROR

17.2.457.1.3. Fortran 2008 Syntax

USE mpi_f08
MPI_Win_start(group, assert, win, ierror)
     TYPE(MPI_Group), INTENT(IN) :: group
     INTEGER, INTENT(IN) :: assert
     TYPE(MPI_Win), INTENT(IN) :: win
     INTEGER, OPTIONAL, INTENT(OUT) :: ierror

17.2.457.2. INPUT PARAMETERS

  • group: The group of target processes (handle).

  • assert: Program assertion (integer).

  • win: Window object (handle).

17.2.457.3. OUTPUT PARAMETERS

  • IERROR: Fortran only: Error status (integer).

17.2.457.4. DESCRIPTION

MPI_Win_start is a one-sided MPI communication synchronization call that starts an RMA access epoch for win. RMA calls issued on win during this epoch must access only windows at processes in group. Each process in group must issue a matching call to MPI_Win_post. MPI_Win_start is allowed to block until the corresponding MPI_Win_post calls have been executed, but is not required to.

The assert argument is used to provide assertions on the context of the call that may be used for various optimizations. (See Section 6.4.4 of the MPI-2 Standard.) A value of assert = 0 is always valid. The following assertion value is supported:

MPI_MODE_NOCHECK

When this value is passed in to this call, the library assumes that the post call on the target has been called and it is not necessary for the library to check to see if such a call has been made.

17.2.457.5. ERRORS

Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument.

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_Win_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.