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MPI_File_read - Reads a file starting at the location specified by
the individual file pointer (blocking, noncollective).
C Syntax
#include <mpi.h>
int MPI_File_read(MPI_File fh, void *buf,
int count, MPI_Datatype datatype, MPI_Status *status)
INCLUDE ’mpif.h’
MPI_FILE_READ( FH, BUF, COUNT,
DATATYPE, STATUS, IERROR)
<type> BUF(*)
INTEGER FH, COUNT, DATATYPE, STATUS(MPI_STATUS_SIZE),
IERROR
#include <mpi.h>
void MPI::File::Read(void* buf, int count,
const MPI::Datatype& datatype, MPI::Status& status)
void MPI::File::Read(void* buf, int count,
const MPI::Datatype& datatype)
- fh
- File handle (handle).
- count
- Number of elements in buffer
(integer).
- datatype
- Data type of each buffer element (handle).
- buf
- Initial address of buffer (integer).
- status
- Status object (status).
- IERROR
- Fortran only: Error status (integer).
MPI_File_read 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. MPI_File_read
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.
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.
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