MPI_File_read_all_begin(3)         Open MPI         MPI_File_read_all_begin(3)



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
           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.




1.4.1                            Jan 14, 2010       MPI_File_read_all_begin(3)
