MONGOC_CLIENT_T(3) libmongoc MONGOC_CLIENT_T(3) A single-threaded MongoDB connection. See Connection Pooling. SYNOPSIS typedef struct _mongoc_client_t mongoc_client_t; typedef mongoc_stream_t *(*mongoc_stream_initiator_t) ( const mongoc_uri_t *uri, const mongoc_host_list_t *host, void *user_data, bson_error_t *error); mongoc_client_t is an opaque type that provides access to a MongoDB server, replica set, or sharded cluster. It maintains management of underlying sockets and routing to individual nodes based on mongoc_read_prefs_t or mongoc_write_concern_t. STREAMS The underlying transport for a given client can be customized, wrapped or replaced by any implementation that fulfills mongoc_stream_t. A custom transport can be set with mongoc_client_set_stream_initiator(). THREAD SAFETY mongoc_client_t is NOT thread-safe and should only be used from one thread at a time. When used in multi-threaded scenarios, it is recommended that you use the thread-safe mongoc_client_pool_t to retrieve a mongoc_client_t for your thread. FORK SAFETY A mongoc_client_t is only usable in the parent process after a fork. The child process must call mongoc_client_reset(). EXAMPLE example-client.c /* gcc example-client.c -o example-client $(pkg-config --cflags --libs * libmongoc-1.0) */ /* ./example-client [CONNECTION_STRING [COLLECTION_NAME]] */ #include <mongoc/mongoc.h> #include <stdio.h> #include <stdlib.h> int main (int argc, char *argv[]) { mongoc_client_t *client; mongoc_collection_t *collection; mongoc_cursor_t *cursor; bson_error_t error; const bson_t *doc; const char *collection_name = "test"; bson_t query; char *str; const char *uri_string = "mongodb://127.0.0.1/?appname=client-example"; mongoc_uri_t *uri; mongoc_init (); if (argc > 1) { uri_string = argv[1]; } if (argc > 2) { collection_name = argv[2]; } 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; } client = mongoc_client_new_from_uri (uri); if (!client) { return EXIT_FAILURE; } mongoc_client_set_error_api (client, 2); bson_init (&query); collection = mongoc_client_get_collection (client, "test", collection_name); cursor = mongoc_collection_find_with_opts (collection, &query, NULL, /* additional options */ NULL); /* read prefs, NULL for default */ while (mongoc_cursor_next (cursor, &doc)) { str = bson_as_canonical_extended_json (doc, NULL); fprintf (stdout, "%s\n", str); bson_free (str); } if (mongoc_cursor_error (cursor, &error)) { fprintf (stderr, "Cursor Failure: %s\n", error.message); return EXIT_FAILURE; } bson_destroy (&query); mongoc_cursor_destroy (cursor); mongoc_collection_destroy (collection); mongoc_uri_destroy (uri); mongoc_client_destroy (client); mongoc_cleanup (); return EXIT_SUCCESS; } AUTHOR MongoDB, Inc COPYRIGHT 2009-present, MongoDB, Inc. 1.30.8 Aug 27, 2026 MONGOC_CLIENT_T(3)
SYNOPSIS | STREAMS | THREAD SAFETY | FORK SAFETY | EXAMPLE | AUTHOR | COPYRIGHT
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