---
name: "MPI_Win_Lock"
section: "3"
platform: "linux"
package: "lam-mpidoc"
version: "7.1.4-7.2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/MPI_Win_Lock"
---

# MPI\_Win\_Lock(3)

Starts an RMA access epoch

## NAME

MPI\_Win\_Lock -  Starts an RMA access epoch

## SYNOPSIS

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

## 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)

## NOTES

This function is currently not implemented in LAM/MPI.  It will return an MPI\_ERR\_OTHER run time error.

## 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.

## LOCATION

wlock.c