The Great and Terrible implementation of MPI-2

function index


Add and MPI error code to an MPI error class
int MPI_Add_error_code(
  int errorclass,
  int *errorcode


[in] Error class to add an error code.
[out] New error code for this error class.


Creates new error code associated with errorclass and returns its value in errorcode.

Rationale: To avoid conflicts with existing error codes and classes, the value of the new error code is set by the implementation and not by the user.

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 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.
Other error; use MPI_Error_string to get more information about this error code.

Example Code

The following sample code illustrates MPI_Add_error_code.

#include "mpi.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

/* Create NCLASSES new classes, each with 5 codes (160 total) */
#define NCLASSES 32
#define NCODES 5

int main( int argc, char *argv[] )
    int errs = 0;
int newclass[NCLASSES], newcode[NCLASSES][NCODES];
int i, j, slen, outclass;

    MPI_Init( &argc, &argv );
/* Initialize the new codes */
for (i=0; i<NCLASSES; i++) {
        MPI_Add_error_class( &newclass[i] );
for (j=0; j<NCODES; j++) {
            MPI_Add_error_code( newclass[i], &newcode[i][j] );
            sprintf( string, "code for class %d code %d\n", i, j );
            MPI_Add_error_string( newcode[i][j], string );
/* check the values */
for (i=0; i<NCLASSES; i++) {
        MPI_Error_class( newclass[i], &outclass );
if (outclass != newclass[i]) {
            printf( "Error class %d is not a valid error code %x %x\n", i,
                        outclass, newclass[i]);fflush(stdout);
for (j=0; j<NCODES; j++) {
            MPI_Error_class( newcode[i][j], &outclass );
if (outclass != newclass[i]) {
                printf( "Class of code for %d is not correct %x %x\n", j,
                            outclass, newclass[i] );fflush(stdout);
            MPI_Error_string( newcode[i][j], outstring, &slen );
            sprintf( string, "code for class %d code %d\n", i, j );
if (strcmp( outstring, string )) {
                printf( "Error string is :%s: but should be :%s:\n",
                            outstring, string );fflush(stdout);
return 0;