A stepwise resource allocation in C. Example for http://softwareengineering.stackexchange.com/questions/335851/

forest.c

int f() {
	FILE *fp = NULL;
	Forest* forest = NULL;
	Tree *tree = NULL;
	Element *element = NULL;
	int status = 0;
			
	fp = fopen("data.txt", "rb");
	forest = generate_forest(fp, ...);
	if (!forest) {
		status = 1;
		goto exit;
	}
	
	tree = get_tree(forest, "SPAIN"...);
	if (!tree) {
		status = 1;
		goto exit;
	}
	
	element = malloc(sizeof(element));
	if (!element) {
		status = 1;
		goto exit;
	}
	element->value = MAGIC;
	
	if (tree_add(tree, element) != 0) goto exit;

//	...
	
exit:
	if (status != 0)
		global_logger.error("There's a problem in the forest!");
	
	if (element)
		free (element);
	if (forest)
		release_forest (forest);
	if (fp)
		fclose (fp);
	
	return status;
}