NAME

       MPI_File_read_all_begin  -  Reads a file starting at the locations specified by individual
       file pointers; beginning part of a split collective routine (nonblocking).

SYNTAX

C Syntax

       #include <mpi.h> int  MPI_File_read_all_begin(MPI_File  fh,  void  *buf,       int  count,
       MPI_Datatype datatype)

Fortran Syntax

       USE MPI
       ! or the older form: INCLUDE 'mpif.h'
       MPI_FILE_READ_ALL_BEGIN(FH, BUF, COUNT, DATATYPE, IERROR)
            <type>    BUF(*)
            INTEGER   FH, COUNT, DATATYPE, IERROR

C++ Syntax

       #include <mpi.h>
       void MPI::File::Read_all_begin(void* buf, int count,
            const MPI::Datatype& datatype)

INPUT/OUTPUT PARAMETER

       fh        File handle (handle).

INPUT PARAMETERS

       count     Number of elements in buffer (integer).

       datatype  Data type of each buffer element (handle).

OUTPUT PARAMETERS

       buf       Initial address of buffer (choice).

       IERROR    Fortran only: Error status (integer).

DESCRIPTION

       MPI_File_read_all_begin  is  the  beginning  part  of  a  split  collective operation that
       attempts to read from 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
       into the user's buffer buf.  The data is taken out of those parts of the file specified by
       the current view.

NOTES

       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 Section 9.4.5 of the MPI-2 standard.

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++ functions 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.