MPI_Abort(3)							      LAM/MPI							      MPI_Abort(3)

NAME

       MPI_Abort -  Terminates MPI execution environment

SYNOPSIS

       #include <mpi.h>
       int MPI_Abort(MPI_Comm comm, int errcode)

INPUT PARAMETERS

       comm   - communicator of tasks to abort
       errcode
	      - error code to return to invoking environment

NOTES

       Makes  a  "best	attempt" to terminate all MPI processes associated with the communicator comm ; for non-IMPI jobs, this will terminate all
       processes.  MPI_Abort will hang, however, if the LAM daemon on the node on which a rank was running has died.  For example, if a node  gets
       powered off in the middle of an MPI run and MPI_Abort is invoked, it may hang trying to contact the LAM daemon on the downed node.

       In  the	case  of  an IMPI job, in addition to terminating all local IMPI procs, this function will also send an abort message to the local
       IMPI host, which will, in turn send "closing" messages to all the other IMPI hosts.  Their behavior upon receipt of  these  "closing"  mes-
       sages is implementation dependant.

       If  the LAM IMPI host receives a premature "closing" message from a remote IMPI host, it will attempt to continue processing.  Any new mes-
       sages to that host will likely hang, however.

'ERRCODE' IS SPLIT INTO THREE SECTIONS
       lower 8 bits: error class
	      - . next 8 bits: function
       upper 16 bits: error code
	      - If the error class is nonzero, the error code is the POSIX return value for the  program  (i.e.,  exit(error_code)  is	eventually
	      called to terminate the program).  If the error class is zero, errcode is returned as the POSIX return value for the program.

	      This  is mainly because MPI_Abort is used internally in LAM/MPI to abort MPI upon error; LAM packs all three pieces of data into the
	      POSIX return code.  Users who wish to return a specific value from the

PROGRAM SHOULD USE SOMETHING SIMILAR TO

       return ((return_code << 16) + 1);

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.

MORE INFORMATION

       For more information, please see the official MPI Forum web site, which contains the text of both the MPI-1  and  MPI-2	standards.   These
       documents contain detailed information about each MPI function (most of which is not duplicated in these man pages).

       http://www.mpi-forum.org/

ACKNOWLEDGEMENTS

       The LAM Team would like the thank the MPICH Team for the handy program to generate man pages ("doctext" from ftp://ftp.mcs.anl.gov/pub/sow-
       ing/sowing.tar.gz ), the initial formatting, and some initial text for most of the MPI-1 man pages.

LOCATION

       abort.c

LAM
/MPI 6.5.8							    11/10/2002							      MPI_Abort(3)