+#include <stdio.h>
+#include <string.h>
+#include "config.h"
+
+/**
+ * idtree - id allocation tree
+ *
+ * There are often cases where you want to provide an integer handle for
+ * some data, and easily map it back to another structure.
+ *
+ * idtree is an efficient implementation of an int->void * mapping, with
+ * assignment of the lowest available id number. It is from the Linux kernel
+ * via the Samba project.
+ *
+ * Example:
+ * #include <ccan/idtree/idtree.h>
+ * #include <ccan/talloc/talloc.h>
+ * #include <stdlib.h>
+ * #include <stdio.h>
+ *
+ * // Silly example which puts args in the idtree and retreives them
+ * int main(int argc, char *argv[])
+ * {
+ * struct idtree *idtree = idtree_new(NULL);
+ * unsigned int i;
+ *
+ * // This will return consecutive id numbers.
+ * for (i = 0; i < argc; i++) {
+ * printf("idtree_add('%s') -> id %i\n",
+ * argv[i], idtree_add(idtree, argv[i], -1));
+ * }
+ * for (i = 0; i < argc; i++) {
+ * printf("id %i -> '%s'\n", i, idtree_lookup(idtree, i));
+ * }
+ * return 0;
+ * }
+ *
+ * Licence: GPL (2 or any later version)
+ * Maintainer: Rusty Russell <rusty@rustcorp.com.au>
+ * Author: Jim Houston <jim.houston@ccur.com>
+ */
+int main(int argc, char *argv[])
+{
+ if (argc != 2)
+ return 1;
+
+ if (strcmp(argv[1], "depends") == 0) {
+ printf("ccan/talloc\n");
+ return 0;
+ }
+
+ return 1;
+}