NAME

MPI_Errhandler_create - Creates an error handler from a user function

SYNOPSIS

#include <mpi.h> 
int MPI_Errhandler_create(MPI_Handler_function *func , MPI_Errhandler *errh ); 
#include <pmpi.h> 
int PMPI_Errhandler_create(MPI_Handler_function *func , MPI_Errhandler *errh ); 

INPUT PARAMETER

func - error handling function (function pointer)

OUTPUT PARAMETER

errh - the new error handler handle (handle).

DESCRIPTION

The MPI_Errhandler_create() function is used to create an error handler handle errh from a user function, func . The handle may then be used to change the behaviour on error of communicators.

The handle should eventually be freed by the MPI_Errhandler_free() function.

Two default handles already exist. MPI_ERRORS_ARE_FATAL is the default handler that aborts with an error message. MPI_ERRORS_RETURN is a handler that will cause a failing function to return an error code.

PMPI_Errhandler_create() is the profiling version of this function.

The form of MPI_Handler_function is

typedef void MPI_Handler_function(MPI_Comm comm , int *err , ...); 

INPUT PARAMETERS

comm - communicator (handle)

err - error code (integer)

OUTPUT PARAMETERS

err - error code (integer)

HANDLER FUNCTIONS

The handler function should in some way "handle" the error condition. The communicator corresponding to the error is passed to this function in comm . The error code is passed in err . However, note that err is passed via pointer. This allows the handler function to alter the error code condition. The resulting value will be returned to the user code calling the failing MPI routine via its return value.

The variable argument list contains one extra parameter, the name of the failing function. Note that this may not be a top-level routine exposed by the MPI interface, and could be the name of a low-level undocumented routine. This extra parameter is encoded as a C string, and may be accessed by using the va_args macros:

	void example_handle_func(MPI_Comm *comm, int *err, ...)
 	{	
 		va_list ap;
 		const char *func;
 
		va_start(ap, err);
 		func = va_arg(ap, const char *);
 		va_end(ap);
 
		printf("Failing function: %sn", func);
 	}
 

ERRORS

All MPI routines except for MPI_Wtime and MPI_Wtick return an error value. The the current MPI error handler is invoked if this return value is not MPI_SUCCESS. The default error handler aborts, but this may be changed with by using the MPI_Errhandler_set() function. The predefined error handler MPI_ERRORS_RETURN may be used to cause error values to be returned instead. Note that MPI does not guarentee that an MPI program can continue past an error. In this implementation, all errors except MPI_ERR_INTERN or MPI_ERR_OTHER should always be recoverable.

MPI_SUCCESS - No error;

MPI_ERR_ARG - Invalid handle pointer.

SEE ALSO

MPI_ERRORS_ARE_FATAL (3) MPI_ERRORS_RETURN (3) MPI_Errhandler_free (3) MPI_Errhandler_set (3) MPI_Errhandler_get (3) MPI_Error_string (3) MPI_Error_class (3)

• Lockless
• MPI Documentation
• MPI_Errhandler_create