typedef struct _mongoc_client_pool_t mongoc_client_pool_t

/* gcc example-pool.c -o example-pool $(pkg-config --cflags --libs


 * libmongoc-1.0) */
/* ./example-pool [CONNECTION_STRING] */
#include <mongoc/mongoc.h>
#include <pthread.h>
#include <stdio.h>
static pthread_mutex_t mutex;
static bool in_shutdown = false;
static void *
worker (void *data)
{


   mongoc_client_pool_t *pool = data;


   mongoc_client_t *client;


   bson_t ping = BSON_INITIALIZER;


   bson_error_t error;


   bool r;


   BSON_APPEND_INT32 (&ping, "ping", 1);


   while (true) {


      client = mongoc_client_pool_pop (pool);


      /* Do something with client. If you are writing an HTTP server, you


       * probably only want to hold onto the client for the portion of the


       * request performing database queries.


       */


      r = mongoc_client_command_simple (


         client, "admin", &ping, NULL, NULL, &error);


      if (!r) {


         fprintf (stderr, "%s\n", error.message);


      }


      mongoc_client_pool_push (pool, client);


      pthread_mutex_lock (&mutex);


      if (in_shutdown || !r) {


         pthread_mutex_unlock (&mutex);


         break;


      }


      pthread_mutex_unlock (&mutex);


   }


   bson_destroy (&ping);


   return NULL;
}
int
main (int argc, char *argv[])
{


   const char *uri_string = "mongodb://127.0.0.1/?appname=pool-example";


   mongoc_uri_t *uri;


   bson_error_t error;


   mongoc_client_pool_t *pool;


   pthread_t threads[10];


   unsigned i;


   void *ret;


   pthread_mutex_init (&mutex, NULL);


   mongoc_init ();


   if (argc > 1) {


      uri_string = argv[1];


   }


   uri = mongoc_uri_new_with_error (uri_string, &error);


   if (!uri) {


      fprintf (stderr,


               "failed to parse URI: %s\n"


               "error message:       %s\n",


               uri_string,


               error.message);


      return EXIT_FAILURE;


   }


   pool = mongoc_client_pool_new (uri);


   mongoc_client_pool_set_error_api (pool, 2);


   for (i = 0; i < 10; i++) {


      pthread_create (&threads[i], NULL, worker, pool);


   }


   sleep (10);


   pthread_mutex_lock (&mutex);


   in_shutdown = true;


   pthread_mutex_unlock (&mutex);


   for (i = 0; i < 10; i++) {


      pthread_join (threads[i], &ret);


   }


   mongoc_client_pool_destroy (pool);


   mongoc_uri_destroy (uri);


   mongoc_cleanup ();


   return EXIT_SUCCESS;
}