1MONGOC_CLIENT_T(3)                 libmongoc                MONGOC_CLIENT_T(3)
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5A single-threaded MongoDB connection. See Connection Pooling.
6

SYNOPSIS

8          typedef struct _mongoc_client_t mongoc_client_t;
9
10          typedef mongoc_stream_t *(*mongoc_stream_initiator_t) (
11             const mongoc_uri_t *uri,
12             const mongoc_host_list_t *host,
13             void *user_data,
14             bson_error_t *error);
15
16       mongoc_client_t  is  an  opaque  type that provides access to a MongoDB
17       server, replica set, or sharded cluster. It maintains management of un‐
18       derlying   sockets   and   routing   to   individual   nodes  based  on
19       mongoc_read_prefs_t or mongoc_write_concern_t.
20

STREAMS

22       The underlying transport for a given client can be customized,  wrapped
23       or replaced by any implementation that fulfills mongoc_stream_t. A cus‐
24       tom transport can be set with mongoc_client_set_stream_initiator().
25

THREAD SAFETY

27       mongoc_client_t is NOT thread-safe and should only  be  used  from  one
28       thread  at  a time. When used in multi-threaded scenarios, it is recom‐
29       mended that you use the thread-safe mongoc_client_pool_t to retrieve  a
30       mongoc_client_t for your thread.
31

FORK SAFETY

33       A  mongoc_client_t  is  only usable in the parent process after a fork.
34       The child process must call mongoc_client_reset().
35

EXAMPLE

37       example-client.c
38
39          /* gcc example-client.c -o example-client $(pkg-config --cflags --libs
40           * libmongoc-1.0) */
41
42          /* ./example-client [CONNECTION_STRING [COLLECTION_NAME]] */
43
44          #include <mongoc/mongoc.h>
45          #include <stdio.h>
46          #include <stdlib.h>
47
48          int
49          main (int argc, char *argv[])
50          {
51             mongoc_client_t *client;
52             mongoc_collection_t *collection;
53             mongoc_cursor_t *cursor;
54             bson_error_t error;
55             const bson_t *doc;
56             const char *collection_name = "test";
57             bson_t query;
58             char *str;
59             const char *uri_string = "mongodb://127.0.0.1/?appname=client-example";
60             mongoc_uri_t *uri;
61
62             mongoc_init ();
63             if (argc > 1) {
64                uri_string = argv[1];
65             }
66
67             if (argc > 2) {
68                collection_name = argv[2];
69             }
70
71             uri = mongoc_uri_new_with_error (uri_string, &error);
72             if (!uri) {
73                fprintf (stderr,
74                         "failed to parse URI: %s\n"
75                         "error message:       %s\n",
76                         uri_string,
77                         error.message);
78                return EXIT_FAILURE;
79             }
80
81             client = mongoc_client_new_from_uri (uri);
82             if (!client) {
83                return EXIT_FAILURE;
84             }
85
86             mongoc_client_set_error_api (client, 2);
87
88             bson_init (&query);
89             collection = mongoc_client_get_collection (client, "test", collection_name);
90             cursor = mongoc_collection_find_with_opts (
91                collection,
92                &query,
93                NULL,  /* additional options */
94                NULL); /* read prefs, NULL for default */
95
96             while (mongoc_cursor_next (cursor, &doc)) {
97                str = bson_as_canonical_extended_json (doc, NULL);
98                fprintf (stdout, "%s\n", str);
99                bson_free (str);
100             }
101
102             if (mongoc_cursor_error (cursor, &error)) {
103                fprintf (stderr, "Cursor Failure: %s\n", error.message);
104                return EXIT_FAILURE;
105             }
106
107             bson_destroy (&query);
108             mongoc_cursor_destroy (cursor);
109             mongoc_collection_destroy (collection);
110             mongoc_uri_destroy (uri);
111             mongoc_client_destroy (client);
112             mongoc_cleanup ();
113
114             return EXIT_SUCCESS;
115          }
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117

AUTHOR

119       MongoDB, Inc
120

122       2017-present, MongoDB, Inc
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1271.25.1                           Nov 08, 2023               MONGOC_CLIENT_T(3)
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