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mpi_init_thread(3openmpi) [osx man page]

MPI_Init_thread(3OpenMPI)												 MPI_Init_thread(3OpenMPI)

NAME
MPI_Init_thread - Initializes the MPI execution environment SYNTAX
C Syntax #include <mpi.h> int MPI_Init_thread(int *argc, char ***argv, int required, int *provided) Fortran Syntax INCLUDE 'mpif.h' MPI_INIT(REQUIRED, PROVIDED, IERROR) INTEGER REQUIRED, PROVIDED, IERROR C++ Syntax #include <mpi.h> int MPI::Init_thread(int& argc, char**& argv, int required) int MPI::Init_thread(int required) INPUT PARAMETERS
argc C/C++ only: Pointer to the number of arguments. argv C/C++ only: Argument vector. required Desired level of thread support (integer). OUTPUT PARAMETERS
provided Available level of thread support (integer). IERROR Fortran only: Error status (integer). DESCRIPTION
This routine, or MPI_Init, must be called before any other MPI routine (apart from MPI_Initialized) is called. MPI can be initialized at most once; subsequent calls to MPI_Init or MPI_Init_thread are erroneous. MPI_Init_thread, as compared to MPI_Init, has a provision to request a certain level of thread support in required: MPI_THREAD_SINGLE Only one thread will execute. MPI_THREAD_FUNNELED If the process is multithreaded, only the thread that called MPI_Init_thread will make MPI calls. MPI_THREAD_SERIALIZED If the process is multithreaded, only one thread will make MPI library calls at one time. MPI_THREAD_MULTIPLE If the process is multithreaded, multiple threads may call MPI at once with no restrictions. The level of thread support available to the program is set in provided, except in C++, where it is the return value of the function. In Open MPI, the value is dependent on how the library was config- ured and built. Note that there is no guarantee that provided will be greater than or equal to required. 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_thread(&argc, &argv, req, &prov); /* parse arguments */ /* main program */ MPI_Finalize(); } NOTES
The Fortran version does not have provisions for argc and argv and takes only IERROR. It is the caller's responsibility to check the value of provided, as it may be less than what was requested in required. The MPI Standard does not say what a program can do before an MPI_Init_thread 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, read- ing 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 ALSO
MPI_Init MPI_Initialized MPI_Finalize Open MPI 1.2 September 2006 MPI_Init_thread(3OpenMPI)

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MPI_Finalize(3) 							MPI							   MPI_Finalize(3)

NAME
MPI_Finalize - Terminates MPI execution environment SYNOPSIS
int MPI_Finalize( void ) NOTES
All processes must call this routine before exiting. The number of processes running after this routine is called is undefined; it is best not to perform much more than a return rc after calling MPI_Finalize . THREAD AND SIGNAL SAFETY
The MPI standard requires that MPI_Finalize be called only by the same thread that initialized MPI with either MPI_Init or MPI_Init_thread . 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. 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. LOCATION
finalize.c 8/11/2010 MPI_Finalize(3)
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