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¶
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)
- fh
- File handle (handle).
- 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.