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/*
igraph library.
Copyright (C) 2006-2022 The igraph development team
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA
*/
#include <igraph.h>
#include <stdio.h>
#include <unistd.h> /* unlink */
int main(void) {
igraph_t graph;
const char *infilename = "test.graphml";
const char *outfilename = "test2.graphml";
/* Initialize the library. */
igraph_setup();
/* Set up attribute handling, so graph attributes can be imported
* from the GraphML file. */
igraph_set_attribute_table(&igraph_cattribute_table);
/* Problems in the GraphML file may cause igraph to print warnings.
* If this is not desired, set a silent warning handler: */
igraph_set_warning_handler(&igraph_warning_handler_ignore);
/* Read the contents of a GraphML file. */
/* GraphML */
FILE *infile = fopen("test.graphml", "r");
if (! infile) {
fprintf(stderr, "Could not open input file '%s'.", infilename);
exit(1);
}
/* GraphML support is an optional feature in igraph. If igraph was compiled
* without GraphML support, igraph_read_graph_graphml() returns IGRAPH_UNIMPLEMENTED.
* We temporarily disable the default error handler so we can test for this condition. */
igraph_error_handler_t *oldhandler = igraph_set_error_handler(igraph_error_handler_ignore);
igraph_error_t ret = igraph_read_graph_graphml(&graph, infile, 0);
if (ret == IGRAPH_UNIMPLEMENTED) {
fprintf(stderr, "igraph was compiled without GraphML support.");
exit(77);
}
if (ret != IGRAPH_SUCCESS) {
fprintf(stderr, "Unexpected error while reading GraphML.");
exit(1);
}
igraph_set_error_handler(oldhandler);
fclose(infile);
/* Write it back into another file. */
FILE *outfile = fopen(outfilename, "w");
if (outfile) {
igraph_write_graph_graphml(&graph, outfile, true);
fclose(outfile);
/* Clean up after ourselves */
unlink(outfilename);
} else {
fprintf(stderr, "Could not write output file '%s'.", outfilename);
}
/* Destroy the graph */
igraph_destroy(&graph);
return 0;
}
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