1MONGOC_CLIENT_T(3) libmongoc MONGOC_CLIENT_T(3)
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6 mongoc_client_t - mongoc_client_t
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8 A single-threaded MongoDB connection. See connection-pooling.
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11 typedef struct _mongoc_client_t mongoc_client_t;
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13 typedef mongoc_stream_t *(*mongoc_stream_initiator_t) (
14 const mongoc_uri_t *uri,
15 const mongoc_host_list_t *host,
16 void *user_data,
17 bson_error_t *error);
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19 mongoc_client_t is an opaque type that provides access to a MongoDB
20 server, replica set, or sharded cluster. It maintains management of un‐
21 derlying sockets and routing to individual nodes based on mon‐
22 goc_read_prefs_t or mongoc_write_concern_t.
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25 The underlying transport for a given client can be customized, wrapped
26 or replaced by any implementation that fulfills mongoc_stream_t. A cus‐
27 tom transport can be set with mongoc_client_set_stream_initiator().
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30 mongoc_client_t is NOT thread-safe and should only be used from one
31 thread at a time. When used in multi-threaded scenarios, it is recom‐
32 mended that you use the thread-safe mongoc_client_pool_t to retrieve a
33 mongoc_client_t for your thread.
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36 example-client.c
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38 /* gcc example-client.c -o example-client $(pkg-config --cflags --libs
39 * libmongoc-1.0) */
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41 /* ./example-client [CONNECTION_STRING [COLLECTION_NAME]] */
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43 #include <mongoc/mongoc.h>
44 #include <stdio.h>
45 #include <stdlib.h>
46
47 int
48 main (int argc, char *argv[])
49 {
50 mongoc_client_t *client;
51 mongoc_collection_t *collection;
52 mongoc_cursor_t *cursor;
53 bson_error_t error;
54 const bson_t *doc;
55 const char *collection_name = "test";
56 bson_t query;
57 char *str;
58 const char *uri_string = "mongodb://127.0.0.1/?appname=client-example";
59 mongoc_uri_t *uri;
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61 mongoc_init ();
62 if (argc > 1) {
63 uri_string = argv[1];
64 }
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66 if (argc > 2) {
67 collection_name = argv[2];
68 }
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70 uri = mongoc_uri_new_with_error (uri_string, &error);
71 if (!uri) {
72 fprintf (stderr,
73 "failed to parse URI: %s\n"
74 "error message: %s\n",
75 uri_string,
76 error.message);
77 return EXIT_FAILURE;
78 }
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80 client = mongoc_client_new_from_uri (uri);
81 if (!client) {
82 return EXIT_FAILURE;
83 }
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85 mongoc_client_set_error_api (client, 2);
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87 bson_init (&query);
88 collection = mongoc_client_get_collection (client, "test", collection_name);
89 cursor = mongoc_collection_find_with_opts (
90 collection,
91 &query,
92 NULL, /* additional options */
93 NULL); /* read prefs, NULL for default */
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95 while (mongoc_cursor_next (cursor, &doc)) {
96 str = bson_as_canonical_extended_json (doc, NULL);
97 fprintf (stdout, "%s\n", str);
98 bson_free (str);
99 }
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101 if (mongoc_cursor_error (cursor, &error)) {
102 fprintf (stderr, "Cursor Failure: %s\n", error.message);
103 return EXIT_FAILURE;
104 }
105
106 bson_destroy (&query);
107 mongoc_cursor_destroy (cursor);
108 mongoc_collection_destroy (collection);
109 mongoc_uri_destroy (uri);
110 mongoc_client_destroy (client);
111 mongoc_cleanup ();
112
113 return EXIT_SUCCESS;
114 }
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118 MongoDB, Inc
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121 2017-present, MongoDB, Inc
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1261.20.0 Nov 18, 2021 MONGOC_CLIENT_T(3)