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

       USE MPI
       ! or the older form: 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.