MPI_File_read_at_all(3) MPI MPI_File_read_at_all(3)NAME
MPI_File_read_at_all - Collective read using explict offset
SYNOPSIS
int MPI_File_read_at_all(MPI_File mpi_fh, MPI_Offset offset, void *buf,
int count, MPI_Datatype datatype,
MPI_Status *status)
INPUT PARAMETERS
fh - file handle (handle)
offset - file offset (nonnegative integer)
count - number of elements in buffer (nonnegative integer)
datatype
- datatype of each buffer element (handle)
OUTPUT PARAMETERS
buf - initial address of buffer (choice)
status - status object (Status)
NOTES FOR FORTRAN
All MPI routines in Fortran (except for MPI_WTIME and MPI_WTICK ) have an additional argument ierr at the end of the argument list. ierr
is an integer and has the same meaning as the return value of the routine in C. In Fortran, MPI routines are subroutines, and are invoked
with the call statement.
All MPI objects (e.g., MPI_Datatype , MPI_Comm ) are of type INTEGER in Fortran.
LOCATION
read_atall.c
11/2/2007 MPI_File_read_at_all(3)
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MPI_File_read_at_all(3OpenMPI)MPI_File_read_at_all(3OpenMPI)NAME
MPI_File_read_at_all - Reads a file at explicitly specified offsets (blocking, collective).
SYNTAX
C Syntax
#include <mpi.h>
int MPI_File_read_at_all(MPI_File fh, MPI_Offset offset,
void *buf, int count, MPI_Datatype datatype,
MPI_Status *status)
Fortran Syntax (see FORTRAN 77 NOTES)
INCLUDE 'mpif.h'
MPI_FILE_READ_AT_ALL(FH, OFFSET, BUF, COUNT,
DATATYPE, STATUS, IERROR)
<type> BUF(*)
INTEGER FH, COUNT, DATATYPE, STATUS(MPI_STATUS_SIZE), IERROR
INTEGER(KIND=MPI_OFFSET_KIND) OFFSET
C++ Syntax
#include <mpi.h>
void MPI::File::Read_at_all(MPI::Offset offset, void* buf,
int count, const MPI::Datatype& datatype, MPI::Status& status)
void MPI::File::Read_at_all(MPI::Offset offset, void* buf,
int count, const MPI::Datatype& datatype)
INPUT PARAMETERS
fh File handle (handle).
offset File offset (integer).
count Number of elements in buffer (integer).
datatype Data type of each buffer element (handle).
OUTPUT PARAMETERS
buf Initial address of buffer (choice).
status Status object (status).
IERROR Fortran only: Error status (integer).
DESCRIPTION
MPI_File_read_at_all is a 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 relative 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 specified by the current view.
MPI_File_read_at_all stores the number of datatype elements actually read in status. All other fields of status are undefined. It is erro-
neous to call this function if MPI_MODE_SEQUENTIAL mode was specified when the file was opened.
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
syntax
INTEGER*MPI_OFFSET_KIND OFFSET
where MPI_OFFSET_KIND is a constant defined in mpif.h and gives the length of the declared integer in bytes.
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_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(3OpenMPI)