#include "uthash.h"
#include <stdlib.h>   /* malloc */
#include <stdio.h>    /* printf */

typedef struct {
    int id;
    UT_hash_handle hh;
    UT_hash_handle ah;
} example_user_t;

#define EVENS(x) ((((example_user_t*)(x))->id & 1) == 0)

int idcmp(void *_a, void *_b) {
  example_user_t *a = (example_user_t*)_a;
  example_user_t *b = (example_user_t*)_b;
  return (a->id - b->id);
}

int main(int argc,char *argv[]) {
    int i;
    example_user_t *user, *users=NULL, *ausers=NULL;

    /* create elements */
    for(i=0;i<10;i++) {
        user = (example_user_t*)malloc(sizeof(example_user_t));
        user->id = i;
        HASH_ADD_INT(users,id,user);
    }

    for(user=users; user; user=(example_user_t*)(user->hh.next)) {
        printf("user %d\n", user->id);
    }
    printf("users count: %u\n", HASH_CNT(hh,users));

    /* now select some users into ausers */
    HASH_SELECT(ah,ausers,hh,users,EVENS);
    HASH_SRT(ah,ausers,idcmp);

    for(user=ausers; user; user=(example_user_t*)(user->ah.next)) {
        printf("auser %d\n", user->id);
    }
    printf("ausers count: %u\n", HASH_CNT(ah,ausers));
    HASH_CLEAR(ah,ausers);
    printf("cleared ausers.\n");
    printf("ausers count: %u\n", HASH_CNT(ah,ausers));
    for(user=ausers; user; user=(example_user_t*)(user->ah.next)) {
        printf("auser %d\n", user->id);
    }
    printf("users count: %u\n", HASH_CNT(hh,users));
   return 0;
}
