MPI_Initialized(3OpenMPI)MPI_Initialized(3OpenMPI)NAME
MPI_Initialized - Indicates whether MPI_Init has been called.
SYNTAX C Syntax
#include <mpi.h>
int MPI_Initialized(int *flag)
Fortran Syntax
INCLUDE 'mpif.h'
MPI_INITIALIZED(FLAG, IERROR)
LOGICAL FLAG
INTEGER IERROR
C++ Syntax
#include <mpi.h>
bool Is_initialized()
OUTPUT PARAMETERS
flag Flag is true if MPI_Init has been called and false otherwise.
IERROR Fortran only: Error status (integer).
DESCRIPTION
This routine may be used to determine whether MPI_Init has been called. It is the only routine that may be called before MPI_Init is
called.
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++ func-
tions 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 ALSO
MPI_Init
Open MPI 1.2 September 2006 MPI_Initialized(3OpenMPI)
Check Out this Related Man Page
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_Initialized) is called. MPI can be initial-
ized 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 nei-
ther 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++ func-
tions 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)