The Great and Terrible implementation of MPI-2

function index


Call the error handler installed on a window object
int MPI_Win_call_errhandler(
  MPI_Win win,
  int errorcode


[in] window with error handler (handle)
[in] error code (integer)


This function invokes the error handler assigned to the window with the error code supplied. This function returns MPI_SUCCESS in C and C++ and the same value in IERROR if the error handler was successfully called (assuming the process is not aborted and the error handler returns).

Assuming the input parameters are valid, when the error handler is set to MPI_ERRORS_RETURN, this routine will always return MPI_SUCCESS.

Advice to users.

As with communicators, the default error handler for windows is MPI_ERRORS_ARE_FATAL.

Thread and Interrupt Safety

This routine is thread and interrupt safe only if no MPI routine that updates or frees the same MPI object may be called concurrently with this routine.

The MPI standard defined a thread-safe interface but this does not mean that all routines may be called without any thread locks. For example, two threads must not attempt to change the contents of the same MPI_Info object concurrently. The user is responsible in this case for using some mechanism, such as thread locks, to ensure that only one thread at a time makes use of this routine.

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_call_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;