MPIFilereadorderedbegin(3OpenMPI) MPIFilereadorderedbegin(3OpenMPI)

NAME
       MMPPIIFFiilleerreeaaddoorrddeerreeddbbeeggiinn - Reads a file at a location specified by a
       shared file pointer; beginning part of a split collective routine (non-
       blocking).


SSYYNNTTAAXX
       C Syntax
           #include 
           int MPIFilereadorderedbegin(MPIFile fh, void *buf,
                  int count, MPIDatatype datatype)

       Fortran Syntax
           INCLUDE 'mpif.h'
           MPIFILEREADORDEREDBEGIN(FH, BUF, COUNT, DATATYPE, IERROR)
                          BUF(*)
                 INTEGER        FH, COUNT, DATATYPE, IERROR


CC++++ SSyynnttaaxx
       #include 
       void MPI::File::Readorderedbegin(void* buf, int count,
            const MPI::Datatype& datatype)


IINNPPUUTT//OOUUTTPPUUTT PPAARRAAMMEETTEERR
       fh        File handle (handle).


IINNPPUUTT PPAARRAAMMEETTEERRSS
       count     Number of elements in buffer (integer).

       datatype  Data type of each buffer element (handle).


OOUUTTPPUUTT PPAARRAAMMEETTEERRSS
       buf       Initial address of buffer (choice).

       IERROR    Fortran only: Error status (integer).


DESCRIPTION
       MPIFilereadorderedbegin  is  the  beginning part of a split collec-
       tive, nonblocking routine that must be called by all processes  in  the
       communicator  group  associated  with the file handle fh.  Each process
       may pass different argument values for the  datatype  and  count  argu-
       ments. Each process attempts to read, from the file associated with fh,
       a total number of count data items having datatype type into the user's
       buffer  buf.   For each process, the location in the file at which data
       is read is the position at which the shared file pointer would be after
       all  processes  whose ranks within the group are less than that of this
       process had read their data.


NNOOTTEESS
       All the nonblocking collective routines for  data  access  are  "split"
       into  two  routines,  each with begin or end as a suffix. These split
       collective routines are subject to the semantic rules described in Sec-
       tion 9.4.5 of the MPI-2 standard.


EERRRROORRSS
       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::ERRORSTHROWEXCEPTIONS, 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   MPIERRORSRETURN.   The   error   handler  may  be  changed  with
       MPIFileseterrhandler;     the     predefined      error      handler
       MPIERRORSAREFATAL  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                    SeptemberM2P0I06Filereadorderedbegin(3OpenMPI)