GSP
Quick Navigator

Search Site

Unix VPS
A - Starter
B - Basic
C - Preferred
D - Commercial
MPS - Dedicated
Previous VPSs
* Sign Up! *

Support
Contact Us
Online Help
Handbooks
Domain Status
Man Pages

FAQ
Virtual Servers
Pricing
Billing
Technical

Network
Facilities
Connectivity
Topology Map

Miscellaneous
Server Agreement
Year 2038
Credits
 

USA Flag

 

 

Man Pages


Manual Reference Pages  -  MPI_WIN_LOCK (3)

NAME

MPI_Win_lock - Starts an RMA access epoch locking access to a particular rank.

CONTENTS

Syntax
C Syntax
Fortran Syntax
C++ Syntax
Input Parameters
Output Parameter
Description
Notes
Errors
See Also

SYNTAX

C Syntax

#include <mpi.h>
int MPI_Win_lock(int lock_type, int rank, int assert, MPI_Win win)

Fortran Syntax

INCLUDE ’mpif.h’
MPI_WIN_LOCK(LOCK_TYPE, RANK, ASSERT, WIN, IERROR)
        INTEGER LOCK_TYPE, RANK, ASSERT, WIN, IERROR

C++ Syntax

#include <mpi.h>
void MPI::Win::Lock(int lock_type, int rank, int assert) const

INPUT PARAMETERS

lock_type Either MPI_LOCK_EXCLUSIVE or MPI_LOCK_SHARED (state).
rank Rank of locked window (nonnegative integer).
assert Program assertion (integer).
win Window object (handle).

OUTPUT PARAMETER

IERROR Fortran only: Error status (integer).

DESCRIPTION

Starts an RMA access epoch. Locks ensure that only the windows created by specific processes can be accessed by those processes (and by no other processes) during that epoch.

Locks are used to protect accesses to the locked target window effected by RMA calls issued between the lock and unlock call, and to protect local load/store accesses to a locked local window executed between the lock and unlock call. Accesses that are protected by an exclusive lock will not be concurrent at the window site with other accesses to the same window that are lock protected. Accesses that are protected by a shared lock will not be concurrent at the window site with accesses protected by an exclusive lock to the same window.

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.

NOTES

In a client/server environment in which clients connect to a server and create windows that span both the client and the server, if a client or server that has obtained a lock on such a window and then terminates abnormally, the server or other clients may hang in a MPI_Win_lock call, failing to notice that the peer MPI job has terminated.

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.

SEE ALSO

MPI_Win_unlock MPI_Win_lock_all

Search for    or go to Top of page |  Section 3 |  Main Index


1.10.2 MPI_WIN_LOCK (3) Jan 21, 2016

Powered by GSP Visit the GSP FreeBSD Man Page Interface.
Output converted with manServer 1.07.