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mpi_get_count(3openmpi) [osx man page]

MPI_Get_count(3OpenMPI) 												   MPI_Get_count(3OpenMPI)

NAME

       MPI_Get_count  - Gets the number of top-level elements received.

SYNTAX

C Syntax
       #include <mpi.h>
       int MPI_Get_count(MPI_Status *status, MPI_Datatype datatype,
	    int *count)

Fortran Syntax
       INCLUDE 'mpif.h'
       MPI_GET_COUNT(STATUS, DATATYPE, COUNT, IERROR)
	    INTEGER   STATUS(MPI_STATUS_SIZE), DATATYPE, COUNT, IERROR

C++ Syntax
       #include <mpi.h>
       int Status::Get_count(const Datatype& datatype) const

INPUT PARAMETERS

       status	 Return status of receive operation (status).

       datatype  Datatype of each receive buffer element (handle).

OUTPUT PARAMETERS

       count	 Number of received elements (integer).

       IERROR	 Fortran only: Error status (integer).

DESCRIPTION

       Returns	the number of entries received. (We count entries, each of type datatype, not bytes.) The datatype argument should match the argu-
       ment provided by the receive call that set the status variable. (As explained in Section 3.12.5 in the  MPI-1  Standard,  "Use  of  General
       Datatypes in Communication," MPI_Get_count may, in certain situations, return the value MPI_UNDEFINED.)

       The  datatype  argument	is passed to MPI_Get_count to improve performance. A message might be received without counting the number of ele-
       ments it contains, and the count value is often not needed. Also, this allows the same function to be used after a call to MPI_Probe.

NOTES

       If the size of the datatype is zero, this routine will return a count of zero.  If the amount of data in status is not an exact multiple of
       the size of datatype (so that count would not be integral), a count of MPI_UNDEFINED is returned instead.

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_Get_elements

Open MPI 1.2							  September 2006					   MPI_Get_count(3OpenMPI)

Check Out this Related Man Page

MPI_File_write_all(3OpenMPI)											      MPI_File_write_all(3OpenMPI)

NAME

       MPI_File_write_all - Writes a file starting at the locations specified by individual file pointers (blocking, collective).

SYNTAX

       C Syntax
	   #include <mpi.h>
	   int MPI_File_write_all(MPI_File fh, void *buf,
		  int count, MPI_Datatype datatype, MPI_Status *status)

       Fortran Syntax
	   INCLUDE 'mpif.h'
	   MPI_FILE_WRITE_ALL(FH,  BUF, COUNT,
		   DATATYPE, STATUS,  IERROR)
	     <type>	   BUF(*)
	     INTEGER  FH, COUNT, DATATYPE, STATUS(MPI_STATUS_SIZE),
		      IERROR

C++ Syntax
       #include <mpi.h>
       void MPI::File::Write_all(const void* buf, int count,
	    const MPI::Datatype& datatype, MPI::Status& status)

       void MPI::File::Write_all(const void* buf, int count,
	    const MPI::Datatype& datatype)

INPUT PARAMETERS

       fh	 File handle (handle).

       buf	 Initial address of buffer (choice).

       count	 Number of elements in buffer (integer).

       datatype  Data type of each buffer element (handle).

OUTPUT PARAMETERS

       status	 Status object (status).

       IERROR	 Fortran only: Error status (integer).

DESCRIPTION

       MPI_File_write_all  is a collective routine that attempts to write into the file associated with fh (at the current individual file pointer
       position maintained by the system) a total number of count data items having datatype type from the user's buffer buf.  The data is written
       into  those  parts of the file specified by the current view. MPI_File_write_all stores the number of datatype elements actually written in
       status.	All other fields of status are undefined.

       It is erroneous to call this function if MPI_MODE_SEQUENTIAL mode was specified when the file was opened.

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. For MPI I/O function errors, the default error handler is  set
       to  MPI_ERRORS_RETURN. The error handler may be changed with MPI_File_set_errhandler; the predefined error handler MPI_ERRORS_ARE_FATAL may
       be used to make I/O errors fatal. Note that MPI does not guarantee that an MPI program can continue past an error.

Open MPI 1.2							  September 2006				      MPI_File_write_all(3OpenMPI)
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