MPI_File_read_at_all_begin - Reads a file at explicitly specified offsets; beginning part of a split collective routine (nonblocking).
int MPI_File_read_at_all_begin(MPI_File fh, MPI_Offset
offset, void *buf, int count, MPI_Datatype
Fortran Syntax (see FORTRAN 77 NOTES)
MPI_FILE_READ_AT_ALL_BEGIN(FH, OFFSET, BUF,
COUNT, DATATYPE, IERROR)
INTEGER FH, COUNT, DATATYPE, IERROR
void MPI::File::Read_at_all_begin(MPI::Offset offset, void* buf,
int count, const MPI::Datatype& datatype)
fh File handle (handle).
offset File offset (integer).
count Number of elements in buffer (integer).
datatype Data type of each buffer element.
buf Initial address of buffer (choice).
IERROR Fortran only: Error status (integer).
MPI_File_read_at_all_begin is the beginning part of a split collective routine that attempts to read from the file associated with fh (at
the offset position) a total number of count data items having datatype type into the user's buffer buf. The offset is in etype units rel-
ative to the current view. That is, holes are not counted when locating an offset. The data is taken out of those parts of the file speci-
fied by the current view.
FORTRAN 77 NOTES
The MPI standard prescribes portable Fortran syntax for the OFFSET argument only for Fortran 90. FORTRAN 77 users may use the non-portable
where MPI_OFFSET_KIND is a constant defined in mpif.h and gives the length of the declared integer in bytes.
All the nonblocking collective routines for data access are "split" into two routines, each with _begin or _end as a suffix. These split
collective routines are subject to the semantic rules described in Section 9.4.5 of the MPI-2 standard.
Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument. C++ func-
tions 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_at_all_begin(3OpenMPI)