NAME

       MPI_File_read - Reads a file starting at the location specified by the individual file pointer (blocking,
       noncollective).

SYNTAX

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

Fortran Syntax

           INCLUDE 'mpif.h'
           MPI_FILE_READ( 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::Read(void* buf, int count,
            const MPI::Datatype& datatype, MPI::Status& status)

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

INPUT PARAMETERS

       fh        File handle (handle).

       count     Number of elements in buffer (integer).

       datatype  Data type of each buffer element (handle).

OUTPUT PARAMETERS

       buf       Initial address of buffer (integer).

       status    Status object (status).

       IERROR    Fortran only: Error status (integer).

DESCRIPTION

       MPI_File_read 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.
       MPI_File_read  stores  the  number  of  data-type  elements actually read 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++ 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.