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MPI_Init(3OpenMPI)                                                                        MPI_Init(3OpenMPI)



NAME
       MPI_Init - Initializes the MPI execution environment


SYNTAX
C Syntax
       #include <mpi.h>
       int MPI_Init(int *argc, char ***argv)


Fortran Syntax
       INCLUDE 'mpif.h'
       MPI_INIT(IERROR)
            INTEGER   IERROR


C++ Syntax
       #include <mpi.h>
       void MPI::Init(int& argc, char**& argv)
       void MPI::Init()


INPUT PARAMETERS
       argc      C/C++ only: Pointer to the number of arguments.

       argv      C/C++ only: Argument vector.


OUTPUT PARAMETER
       IERROR    Fortran only: Error status (integer).


DESCRIPTION
       This  routine,  or  MPI_Init_thread, must be called before any other MPI routine (apart from MPI_Ini-tialized) MPI_Initialized)
       tialized) is called.  MPI  can  be  initialized  at  most  once;  subsequent  calls  to  MPI_Init  or
       MPI_Init_thread are erroneous.

       All  MPI programs must contain a call to MPI_Init or MPI_Init_thread. Open MPI accepts the C/C++ argc
       and argv arguments to main, but neither modifies, interprets, nor distributes them:

            {
                 /* declare variables */
                 MPI_Init(&argc, &argv);
                 /* parse arguments */
                 /* main program */
                 MPI_Finalize();
            }


NOTES
       The Fortran version does not have provisions for argc and argv and takes only IERROR.

       The MPI Standard does not say what a program can do before an MPI_Init or after an  MPI_Finalize.  In
       the  Open  MPI implementation, it should do as little as possible. In particular, avoid anything that
       changes the external state of the program, such as opening files, reading standard input, or  writing
       to standard output.


ERRORS
       Almost  all  MPI  routines return an error value; C routines as the value of the function and Fortran
       routines in the last argument. C++ functions do not return errors. If the default  error  handler  is
       set  to MPI::ERRORS_THROW_EXCEPTIONS, then on error the C++ exception mechanism will be used to throw
       an MPI:Exception object.

       Before the error value is returned, the current MPI error handler is called. By default,  this  error
       handler  aborts  the  MPI  job, except for I/O function errors. The error handler may be changed with
       MPI_Comm_set_errhandler; the predefined error handler MPI_ERRORS_RETURN may be used  to  cause  error
       values  to  be  returned.  Note  that MPI does not guarantee that an MPI program can continue past an
       error.

       See the MPI man page for a full list of MPI error codes.


SEE ALSO
       MPI_Init_thread
       MPI_Initialized
       MPI_Finalize




Open MPI 1.2                                   September 2006                             MPI_Init(3OpenMPI)