MPI_File_read_all_begin(3) Open MPI MPI_File_read_all_begin(3)
NAME
MPI_File_read_all_begin - Reads a file starting at the locations speci-
fied by individual file pointers; beginning part of a split collective
routine (nonblocking).
SYNTAX
C Syntax
#include <mpi.h>
int MPI_File_read_all_begin(MPI_File fh, void *buf,
int count, MPI_Datatype datatype)
Fortran Syntax
USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_FILE_READ_ALL_BEGIN(FH, BUF, COUNT, DATATYPE, IERROR)
<type> BUF(*)
INTEGER FH, COUNT, DATATYPE, IERROR
Fortran 2008 Syntax
USE mpi_f08
MPI_File_read_all_begin(fh, buf, count, datatype, ierror)
TYPE(MPI_File), INTENT(IN) :: fh
TYPE(*), DIMENSION(..), ASYNCHRONOUS :: buf
INTEGER, INTENT(IN) :: count
TYPE(MPI_Datatype), INTENT(IN) :: datatype
INTEGER, OPTIONAL, INTENT(OUT) :: ierror
C++ Syntax
#include <mpi.h>
void MPI::File::Read_all_begin(void* buf, int count,
const MPI::Datatype& datatype)
INPUT/OUTPUT PARAMETER
fh File handle (handle).
INPUT PARAMETERS
count Number of elements in buffer (integer).
datatype Data type of each buffer element (handle).
OUTPUT PARAMETERS
buf Initial address of buffer (choice).
IERROR Fortran only: Error status (integer).
DESCRIPTION
MPI_File_read_all_begin is the beginning part of a split collective op-
eration that 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.
NOTES
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 Sec-
tion 9.4.5 of the MPI-2 standard.
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++ 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_ER-
RORS_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.
4.1.2 Nov 24, 2021 MPI_File_read_all_begin(3)
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