#include <mongoc.h>
#include <stdio.h>
#include <stdlib.h>

int
main (int   argc,
      char *argv[])
{
   bson_error_t error;
   const bson_t *out;
   bson_t *query;
   mongoc_client_t *client;
   mongoc_collection_t *collection;
   mongoc_cursor_t *cursor;

   mongoc_init ();

   client = mongoc_client_new ("mongodb://127.0.0.1:27017/");
   collection = mongoc_client_get_collection (client, "test", "restaurants");
   query = BCON_NEW("$or", "[", "{", "cuisine", "Italian", "}",
                                "{", "address.zipcode", "10036", "}", "]");
   cursor = mongoc_collection_find(collection, MONGOC_QUERY_NONE, 0, 1, 0, query, NULL, NULL);

   if (mongoc_cursor_next(cursor, &out)) {
      printf("document found\n");
   } else if (mongoc_cursor_error(cursor, &error)) {
      printf ("error: %s\n", error.message);
   } else {
      printf("no documents found\n");
   }

   bson_destroy (query);
   mongoc_cursor_destroy (cursor);
   mongoc_collection_destroy (collection);
   mongoc_client_destroy (client);

   mongoc_cleanup ();

   return EXIT_SUCCESS;
}

{ find: "restaurants", or: [ { cuisine: "Italian" }, { address.zipcode: "10036" } ] }