The Great and Terrible implementation of MPI-2

function index


Set window error handler
int MPI_Win_set_errhandler(
  MPI_Win win,
  MPI_Errhandler errhandler


[in] window (handle)
[in] new error handler for window (handle)


Attaches a new error handler to a window. The error handler must be either a predefined error handler, or an error handler created by a call to MPI_WIN_CREATE_ERRHANDLER.

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.


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.

No error; MPI routine completed successfully.
Invalid MPI window object

Example Code

The following sample code illustrates MPI_Win_set_errhandler.

#include "mpi.h"
#include <stdio.h>

/* Test the routines to control error handlers on windows */
static int calls = 0;
static int errs = 0;
static MPI_Win mywin;
static int expected_err_class = MPI_ERR_OTHER;

void weh( MPI_Win *win, int *err, ... )
    int errclass;
    MPI_Error_class( *err, &errclass );
    if (errclass != expected_err_class) {
        printf( "Unexpected error code (class = %d)\n", errclass );fflush(stdout);
    if (*win != mywin) {
        printf( "Unexpected window (got %x expected %x)\n", (int)*win, (int)mywin );fflush(stdout);

int main( int argc, char *argv[] )
    int err;
    int buf[2];
    MPI_Win       win;
    MPI_Comm      comm;
    MPI_Errhandler newerr, olderr;

    MPI_Init( &argc, &argv );
    comm = MPI_COMM_WORLD;
    MPI_Win_create_errhandler( weh, &newerr );

    MPI_Win_create( buf, 2*sizeof(int), sizeof(int), MPI_INFO_NULL, comm, &win );
    mywin = win;
    MPI_Win_get_errhandler( win, &olderr );
    if (olderr != MPI_ERRORS_ARE_FATAL) {
        printf( "Expected errors are fatal\n" );fflush(stdout);

    MPI_Win_set_errhandler( win, newerr );
    expected_err_class = MPI_ERR_RANK;
    err = MPI_Put( buf, 1, MPI_INT, -5, 0, 1, MPI_INT, win );
    if (calls != 1) {
        errs ++;
        printf( "newerr not called\n" );fflush(stdout);
        calls = 1;
    expected_err_class = MPI_ERR_OTHER;
    MPI_Win_call_errhandler( win, MPI_ERR_OTHER );
    if (calls != 2) {
        errs ++;
        printf( "newerr not called (2)\n" );fflush(stdout);

    MPI_Win_free( &win );
    MPI_Errhandler_free( &newerr );

    return errs;