.\" This manpage is Copyright (C) 2016 MongoDB, Inc.
.\" 
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.\" under the terms of the GNU Free Documentation License, Version 1.3
.\" or any later version published by the Free Software Foundation;
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.\" A copy of the license is included in the section entitled "GNU
.\" Free Documentation License".
.\" 
.TH "MONGOC_CURSOR_T" "3" "2016\(hy10\(hy12" "MongoDB C Driver"
.SH NAME
mongoc_cursor_t \- Client-side cursor abtraction
.SH "SYNOPSIS"

.nf
.nf
typedef struct _mongoc_cursor_t mongoc_cursor_t;
.fi
.fi

.B 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 unknown number of documents. Cursors are lazy, meaning that no network traffic occurs until the first call to
.B mongoc_cursor_next(3)
. At that point we can:

.IP \[bu] 2
Determine which host we've connected to with
.B mongoc_cursor_get_host(3)
.
.IP \[bu] 2
Retrieve more records with repeated calls to
.B mongoc_cursor_next(3)
.
.IP \[bu] 2
Test for more records with
.B mongoc_cursor_more(3)
.IP \[bu] 2
Clone a query to repeat execution at a later point with
.B mongoc_cursor_clone(3)
.
.IP \[bu] 2
Test for errors with
.B mongoc_cursor_error(3)
.

.SH "THREAD SAFETY"

.B mongoc_cursor_t
is
.B NOT
thread safe. It may only be used from the thread it was created from.

.SH "EXAMPLE"

.nf

/* gcc example.c \(hyo example $(pkg\(hyconfig \(hy\(hycflags \(hy\(hylibs libmongoc\(hy1.0) */

/* ./example\(hyclient [CONNECTION_STRING [COLLECTION_NAME]] */

#include <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 *uristr = "mongodb://127.0.0.1/";
   const char *collection_name = "test";
   bson_t query;
   char *str;

   mongoc_init ();

   if (argc > 1) {
      uristr = argv [1];
   }

   if (argc > 2) {
      collection_name = argv [2];
   }

   client = mongoc_client_new (uristr);

   if (!client) {
      fprintf (stderr, "Failed to parse URI.\en");
      return EXIT_FAILURE;
   }

   mongoc_client_set_error_api (client, 2);

   bson_init (&query);

#if 0
   bson_append_utf8 (&query, "hello", \(hy1, "world", \(hy1);
#endif

   collection = mongoc_client_get_collection (client, "test", collection_name);
   cursor = mongoc_collection_find (collection,
                                    MONGOC_QUERY_NONE,
                                    0,
                                    0,
                                    0,
                                    &query,
                                    NULL,  /* Fields, NULL for all. */
                                    NULL); /* Read Prefs, NULL for default */

   while (mongoc_cursor_next (cursor, &doc)) {
      str = bson_as_json (doc, NULL);
      fprintf (stdout, "%s\en", str);
      bson_free (str);
   }

   if (mongoc_cursor_error (cursor, &error)) {
      fprintf (stderr, "Cursor Failure: %s\en", error.message);
      return EXIT_FAILURE;
   }

   bson_destroy (&query);
   mongoc_cursor_destroy (cursor);
   mongoc_collection_destroy (collection);
   mongoc_client_destroy (client);

   mongoc_cleanup ();

   return EXIT_SUCCESS;
}
.fi


.B
.SH COLOPHON
This page is part of MongoDB C Driver.
Please report any bugs at https://jira.mongodb.org/browse/CDRIVER.