NAME

       MPI_File_read_at_all_begin  - Reads a file at explicitly specified offsets; beginning part
       of a split collective routine (nonblocking).

SYNTAX

       C Syntax
           #include <mpi.h>
           int MPI_File_read_at_all_begin(MPI_File fh, MPI_Offset
            offset, void *buf, int count, MPI_Datatype
            datatype)

Fortran Syntax (see FORTRAN 77 NOTES)

           INCLUDE 'mpif.h'
           MPI_FILE_READ_AT_ALL_BEGIN(FH, OFFSET, BUF,
            COUNT, DATATYPE, IERROR)
                 <type> BUF(*)
                 INTEGER   FH, COUNT, DATATYPE, IERROR
                 INTEGER(KIND=MPI_OFFSET_KIND) OFFSET

C++ Syntax

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

INPUT PARAMETERS

       fh        File handle (handle).

       offset    File offset (integer).

       count     Number of elements in buffer (integer).

       datatype  Data type of each buffer element.

OUTPUT PARAMETERS

       buf       Initial address of buffer (choice).

       IERROR    Fortran only: Error status (integer).

DESCRIPTION

       MPI_File_read_at_all_begin is the beginning  part  of  a  split  collective  routine  that
       attempts  to read from the file associated with fh (at the offset position) a total number
       of count data items having datatype type into the user's buffer buf.   The  offset  is  in
       etype  units relative to the current view. That is, holes are not counted when locating an
       offset. The data is taken out of those parts of the file specified by the current view.

FORTRAN 77 NOTES

       The MPI standard prescribes portable Fortran syntax  for  the  OFFSET  argument  only  for
       Fortran 90. FORTRAN 77 users may use the non-portable syntax

            INTEGER*MPI_OFFSET_KIND OFFSET

       where MPI_OFFSET_KIND is a constant defined in mpif.h and gives the length of the declared
       integer in bytes.

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.