bionic (3) MPI_File_iread.openmpi.3.gz

NAME

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

SYNTAX

C Syntax

       #include <mpi.h> int MPI_File_iread(MPI_File fh, void  *buf,  int   count,       MPI_Datatype   datatype,
       MPI_Request  *request)

Fortran Syntax

       USE MPI
       ! or the older form: INCLUDE 'mpif.h'
       MPI_FILE_IREAD(FH, BUF, COUNT, DATATYPE, REQUEST, IERROR)
            <type>    BUF(*)
            INTEGER   FH, COUNT, DATATYPE, REQUEST, IERROR

C++ Syntax

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

INPUT/OUTPUT PARAMETER

       fh        File handle (handle).

INPUT PARAMETERS

       count     Number of elements in the buffer (integer).

       datatype  Data type of each buffer element (handle).

OUTPUT PARAMETERS

       buf       Initial address of buffer (choice).

       request   Request object (handle).

       IERROR    Fortran only: Error status (integer).

DESCRIPTION

       MPI_File_iread  is  a  nonblocking version of MPI_File_read. It attempts to read from the file associated
       with fh at the current individual file pointer position maintained by the system in which a total  number
       of  count data items having datatype type  are read into the user's buffer buf.  The data is taken out of
       those parts of the file specified by the current view. MPI_File_iread  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.