mirror of
https://github.com/HDFGroup/hdf5.git
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228 lines
7.1 KiB
C++
228 lines
7.1 KiB
C++
/*
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* This program shows how the select_hyperslab and select_elements
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* functions are used to write selected data from memory to the file.
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* Program takes 48 elements from the linear buffer and writes them into
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* the matrix using 3x2 blocks, (4,3) stride and (2,4) count.
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* Then four elements of the matrix are overwritten with the new values and
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* file is closed. Program reopens the file and reads and displays the result.
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*/
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#include <string>
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#ifndef H5_NO_NAMESPACE
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using namespace std;
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#endif
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#ifdef OLD_HEADER_FILENAME
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#include <iostream.h>
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#else
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#include <iostream>
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#endif
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#include "H5Cpp.h"
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#ifndef H5_NO_NAMESPACE
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using namespace H5;
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#endif
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const string FILE_NAME( "Select.h5" );
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const string DATASET_NAME( "Matrix in file" );
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const int MSPACE1_RANK = 1; // Rank of the first dataset in memory
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const int MSPACE1_DIM = 50; // Dataset size in memory
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const int MSPACE2_RANK = 1; // Rank of the second dataset in memory
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const int MSPACE2_DIM = 4; // Dataset size in memory
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const int FSPACE_RANK = 2; // Dataset rank as it is stored in the file
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const int FSPACE_DIM1 = 8; // Dimension sizes of the dataset as it is...
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const int FSPACE_DIM2 = 12; // ...stored in the file
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const int MSPACE_DIM1 = 8; // We will read dataset back from the file...
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const int MSPACE_DIM2 = 12; // ...to the dataset in memory with these ...
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// ...dataspace parameters
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const int NPOINTS = 4; // Number of points that will be selected...
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// ...and overwritten
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int main (void)
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{
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/*
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* Buffers' initialization.
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*/
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uint i,j;
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int vector[MSPACE1_DIM];
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vector[0] = vector[MSPACE1_DIM - 1] = -1;
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for (i = 1; i < MSPACE1_DIM - 1; i++)
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vector[i] = i;
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int matrix[MSPACE_DIM1][MSPACE_DIM2];
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for (i = 0; i < MSPACE_DIM1; i++)
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{
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for (j = 0; j < MSPACE_DIM2; j++)
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matrix[i][j] = 0;
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}
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// Try block to detect exceptions raised by any of the calls inside it
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try
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{
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//
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//Create a file.
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//
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H5File* file = new H5File( FILE_NAME, H5F_ACC_TRUNC );
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//
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//Create dataspace for the dataset in the file.
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//
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hsize_t fdim[] = {FSPACE_DIM1, FSPACE_DIM2}; // dim sizes of ds (on disk)
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DataSpace fspace( FSPACE_RANK, fdim );
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//
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// Create dataset and write it into the file.
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//
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DataSet* dataset = new DataSet(
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file->createDataSet( DATASET_NAME, PredType::NATIVE_INT, fspace ));
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dataset->write( matrix, PredType::NATIVE_INT );
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//
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// Select hyperslab for the dataset in the file, using 3x2 blocks,
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// (4,3) stride and (2,4) count starting at the position (0,1).
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//
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hssize_t start[2]; // Start of hyperslab
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hsize_t stride[2]; // Stride of hyperslab
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hsize_t count[2]; // Block count
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hsize_t block[2]; // Block sizes
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start[0] = 0; start[1] = 1;
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stride[0] = 4; stride[1] = 3;
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count[0] = 2; count[1] = 4;
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block[0] = 3; block[1] = 2;
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fspace.selectHyperslab( H5S_SELECT_SET, count, start, stride, block);
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//
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// Create dataspace for the first dataset.
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//
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hsize_t dim1[] = {MSPACE1_DIM}; /* Dimension size of the first dataset
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(in memory) */
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DataSpace mspace1( MSPACE1_RANK, dim1 );
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/*
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* Select hyperslab.
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* We will use 48 elements of the vector buffer starting at the
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* second element. Selected elements are 1 2 3 . . . 48
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*/
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start[0] = 1;
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stride[0] = 1;
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count[0] = 48;
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block[0] = 1;
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mspace1.selectHyperslab( H5S_SELECT_SET, count, start, stride, block);
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/*
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* Write selection from the vector buffer to the dataset in the file.
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*
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* File dataset should look like this:
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* 0 1 2 0 3 4 0 5 6 0 7 8
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* 0 9 10 0 11 12 0 13 14 0 15 16
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* 0 17 18 0 19 20 0 21 22 0 23 24
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* 0 0 0 0 0 0 0 0 0 0 0 0
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* 0 25 26 0 27 28 0 29 30 0 31 32
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* 0 33 34 0 35 36 0 37 38 0 39 40
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* 0 41 42 0 43 44 0 45 46 0 47 48
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* 0 0 0 0 0 0 0 0 0 0 0 0
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*/
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dataset->write( vector, PredType::NATIVE_INT, mspace1, fspace );
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/*
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* Reset the selection for the file dataspace fid.
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*/
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fspace.selectNone();
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/*
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* Create dataspace for the second dataset.
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*/
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hsize_t dim2[] = {MSPACE2_DIM}; /* Dimension size of the second dataset
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(in memory */
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DataSpace mspace2( MSPACE2_RANK, dim2 );
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/*
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* Select sequence of NPOINTS points in the file dataspace.
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*/
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hssize_t coord[NPOINTS][FSPACE_RANK]; /* Array to store selected points
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from the file dataspace */
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coord[0][0] = 0; coord[0][1] = 0;
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coord[1][0] = 3; coord[1][1] = 3;
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coord[2][0] = 3; coord[2][1] = 5;
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coord[3][0] = 5; coord[3][1] = 6;
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fspace.selectElements( H5S_SELECT_SET, NPOINTS, (const hssize_t **)coord);
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/*
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* Write new selection of points to the dataset.
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*/
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int values[] = {53, 59, 61, 67}; /* New values to be written */
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dataset->write( values, PredType::NATIVE_INT, mspace2, fspace );
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/*
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* File dataset should look like this:
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* 53 1 2 0 3 4 0 5 6 0 7 8
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* 0 9 10 0 11 12 0 13 14 0 15 16
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* 0 17 18 0 19 20 0 21 22 0 23 24
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* 0 0 0 59 0 61 0 0 0 0 0 0
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* 0 25 26 0 27 28 0 29 30 0 31 32
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* 0 33 34 0 35 36 67 37 38 0 39 40
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* 0 41 42 0 43 44 0 45 46 0 47 48
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* 0 0 0 0 0 0 0 0 0 0 0 0
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*
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*/
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/*
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* Close the dataset and the file.
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*/
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delete dataset;
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delete file;
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/*
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* Open the file.
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*/
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file = new H5File( FILE_NAME, H5F_ACC_RDONLY );
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/*
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* Open the dataset.
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*/
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dataset = new DataSet( file->openDataSet( DATASET_NAME ));
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/*
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* Read data back to the buffer matrix.
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*/
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dataset->read( matrix, PredType::NATIVE_INT );
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/*
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* Display the result.
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*/
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for (i=0; i < MSPACE_DIM1; i++)
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{
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for(j=0; j < MSPACE_DIM2; j++)
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cout << matrix[i][j] << " ";
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cout << endl;
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}
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/*
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* Close the dataset and the file.
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*/
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delete dataset;
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delete file;
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} // end of try block
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// catch failure caused by the H5File operations
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catch( FileIException error )
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{
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error.printError();
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}
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// catch failure caused by the DataSet operations
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catch( DataSetIException error )
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{
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error.printError();
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}
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// catch failure caused by the DataSpace operations
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catch( DataSpaceIException error )
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{
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error.printError();
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}
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return 0;
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}
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