MPI_Errhandler_getGets the error handler for a communicator
int MPI_Errhandler_get( MPI_Comm comm, MPI_Errhandler *errhandler );
- [in] communicator to get the error handler from (handle)
- [out] MPI error handler currently associated with communicator (handle)
Returns in errhandler (a handle to) the error handler that is currently associated with communicator comm.
Example: A library function may register at its entry point the current error handler for a communicator, set its own private error handler for this communicator, and restore before exiting the previous error handler.
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 FortranAll 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.
Note on Implementation
The MPI Standard was unclear on whether this routine required the user to call MPI_Errhandler_free once for each call made to this routine in order to free the error handler. After some debate, the MPI Forum added an explicit statement that users are required to call MPI_Errhandler_free when the return value from this routine is no longer needed. This behavior is similar to the other MPI routines for getting objects; for example, MPI_Comm_group requires that the user call MPI_Group_free when the group returned by MPI_Comm_group is no longer needed.
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 communicator. A common error is to use a null communicator in a call (not even allowed in MPI_Comm_rank).
- Invalid argument. Some argument is invalid and is not identified by a specific error class (e.g., MPI_ERR_RANK).
The following sample code illustrates MPI_Errhandler_get.