int MPI_Win_free(
  MPI_Win *win
);

Parameters

win

[in] window object (handle)

Remarks

If successfully freed, win is set to MPI_WIN_NULL.

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 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.

MPI_ERR_WIN

Invalid MPI window object

Example Code

The following sample code illustrates MPI_Win_free.

#include "mpi.h"
#include "stdio.h"
 
/* tests put and get with post/start/complete/wait on 2 processes */
 
#define SIZE1 100
#define SIZE2 200
 
int main(int argc, char *argv[])
{
    int rank, destrank, nprocs, *A, *B, i;
    MPI_Group comm_group, group;
    MPI_Win win;
    int errs = 0;
 
    MPI_Init(&argc,&argv);
    MPI_Comm_size(MPI_COMM_WORLD,&nprocs);
    MPI_Comm_rank(MPI_COMM_WORLD,&rank);
    if (nprocs != 2) {
        printf("Run this program with 2 processes\n");fflush(stdout);
        MPI_Abort(MPI_COMM_WORLD,1);
    }
 
    i = MPI_Alloc_mem(SIZE2 * sizeof(int), MPI_INFO_NULL, &A);
    if (i) {
        printf("Can't allocate memory in test program\n");fflush(stdout);
        MPI_Abort(MPI_COMM_WORLD, 1);
    }
    i = MPI_Alloc_mem(SIZE2 * sizeof(int), MPI_INFO_NULL, &B);
    if (i) {
        printf("Can't allocate memory in test program\n");fflush(stdout);
        MPI_Abort(MPI_COMM_WORLD, 1);
    }

    MPI_Comm_group(MPI_COMM_WORLD, &comm_group);
 
    if (rank == 0) {
        for (i=0; i<SIZE2; i++) A[i] = B[i] = i;
        MPI_Win_create(NULL, 0, 1, MPI_INFO_NULL, MPI_COMM_WORLD, &win);
        destrank = 1;
        MPI_Group_incl(comm_group, 1, &destrank, &group);
        MPI_Win_start(group, 0, win);
        for (i=0; i<SIZE1; i++)
            MPI_Put(A+i, 1, MPI_INT, 1, i, 1, MPI_INT, win);
        for (i=0; i<SIZE1; i++)
            MPI_Get(B+i, 1, MPI_INT, 1, SIZE1+i, 1, MPI_INT, win);
 
        MPI_Win_complete(win);
 
        for (i=0; i<SIZE1; i++)
            if (B[i] != (-4)*(i+SIZE1)) {
                printf("Get Error: B[i] is %d, should be %d\n", B[i], (-4)*(i+SIZE1));fflush(stdout);
                errs++;
            }
    }
    else { /* rank=1 */
        for (i=0; i<SIZE2; i++) B[i] = (-4)*i;
        MPI_Win_create(B, SIZE2*sizeof(int), sizeof(int), MPI_INFO_NULL, MPI_COMM_WORLD, &win);
        destrank = 0;
        MPI_Group_incl(comm_group, 1, &destrank, &group);
        MPI_Win_post(group, 0, win);
        MPI_Win_wait(win);

        for (i=0; i<SIZE1; i++) {
            if (B[i] != i) {
                printf("Put Error: B[i] is %d, should be %d\n", B[i], i);fflush(stdout);
                errs++;
            }
        }
    }
 
    MPI_Group_free(&group);
    MPI_Group_free(&comm_group);
    MPI_Win_free(&win);
    MPI_Free_mem(A);
    MPI_Free_mem(B);
 
    MPI_Finalize();
    return errs;
}