This document is a Mac OS X manual page. Manual pages are a command-line technology for providing documentation. You can view these manual pages locally using the man(1) command. These manual pages come from many different sources, and thus, have a variety of writing styles.

For more information about the manual page format, see the manual page for manpages(5).

MPI_File_read(3OpenMPI)                                                              MPI_File_read(3OpenMPI)



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  cur-rent current
       rent  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.




Open MPI 1.2                                   September 2006                        MPI_File_read(3OpenMPI)