MONGOC_CURSOR_T(3) libmongoc MONGOC_CURSOR_T(3) Client-side cursor abstraction SYNOPSIS typedef struct _mongoc_cursor_t mongoc_cursor_t; mongoc_cursor_t provides access to a MongoDB query cursor. It wraps up the wire protocol negotiation required to initiate a query and retrieve an un- known number of documents. Common cursor operations include: * Determine which host we've connected to with mongoc_cursor_get_host(). * Retrieve more records with repeated calls to mongoc_cursor_next(). * Clone a query to repeat execution at a later point with mongoc_cursor_clone(). * Test for errors with mongoc_cursor_error(). Cursors are lazy, meaning that no connection is established and no network traffic occurs until the first call to mongoc_cursor_next(). THREAD SAFETY mongoc_cursor_t is NOT thread safe. It may only be used from within the thread in which it was created. EXAMPLE Query MongoDB and iterate results /* 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_CURSOR_T(3)
SYNOPSIS | THREAD SAFETY | EXAMPLE | AUTHOR | COPYRIGHT
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