MONGOC_CLIENT_POOL_T(3) libmongoc MONGOC_CLIENT_POOL_T(3) A connection pool for multi-threaded programs. See Connection Pooling. 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 dri- ver. 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 struc- ture is thread-safe, except for its destructor method, mongoc_client_pool_destroy(), which is not thread-safe and must only be called from one thread. EXAMPLE example-pool.c /* 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; } AUTHOR MongoDB, Inc COPYRIGHT 2009-present, MongoDB, Inc. 1.30.8 Aug 27, 2026 MONGOC_CLIENT_POOL_T(3)
SYNOPSIS | EXAMPLE | AUTHOR | COPYRIGHT
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