int MPI_Init(
  int *argc,
  char ***argv
);

int MPI_Init(
  int *argc,
  wchar_t ***argv
);

Parameters

argc

[in] Pointer to the number of arguments

argv

[in] Pointer to the argument vector

Remarks

The MPI standard does not say what a program can do before an MPI_INIT or after an MPI_FINALIZE. In the MPICH implementation, you 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.

Thread and Signal Safety

Notes for Fortran

    subroutine MPI_INIT( ierr )
    integer ierr

Errors

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.

MPI_SUCCESS

No error; MPI routine completed successfully.

MPI_ERR_OTHER

This error class is associated with an error code that indicates that an attempt was made to call MPI_INIT a second time. MPI_INIT may only be called once in a program.

See Also

Example Code

The following sample code illustrates MPI_Init.

#include "mpi.h"
#include <stdio.h>
int main(int argc, char *argv[])
{
    int rank, nprocs;

    MPI_Init(&argc,&argv);
    MPI_Comm_size(MPI_COMM_WORLD,&nprocs);
    MPI_Comm_rank(MPI_COMM_WORLD,&rank);
    printf("Hello, world.  I am %d of %d\n", rank, nprocs);fflush(stdout);
    MPI_Finalize();
    return 0;
}