# mongoc_client_pool_t

## Connection pooling abstraction

## Synopsis

    typedef struct _mongoc_client_pool_t mongoc_client_pool_t

mongoc_client_pool_t is the basis for multi-threading in the MongoDB C driver. Since mongoc_client_t structures are not thread-safe, this structure is used to retrieve a new mongoc_client_t for a given thread. This structure is thread-safe.

## Example

    #include <mongoc.h>

    static void *
    worker (void *data)
    {
       mongoc_client_pool_t *pool = data;
       mongoc_client_t *client;

       do {
          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.
           */
          mongoc_client_pool_push (pool, client);
       } while (!inShutdown);

       return NULL;
    }

    int main (int argc, char *argv[])
    {
       mongoc_client_pool_t *pool;
       mongoc_uri_t *uri;
       pthread_t thread[10];
       unsigned i;
       void *ret;

       mongoc_init ();

       uri = mongoc_uri_new ("mongodb://mdb1.example.com/?minPoolSize=16");
       pool = mongoc_client_pool_new (uri);

       for (i = 0; i < 10; i++) {
          pthread_create (&thread, NULL, worker, pool);
       }

       mongoc_uri_destroy (uri);

       for (i = 0; i < 10; i++) {
          pthread_join (threads [i], &ret);
       }

       mongoc_cleanup ();

       return 0;
    }