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PARAMETERS

  • collection: A mongoc_collection_t <>.
  • query: A bson_t <https://www.mongoc.org/libbson/current/bson_t.html> containing the query to locate target document(s).
  • sort: A bson_t <https://www.mongoc.org/libbson/current/bson_t.html> containing the sort order for query.
  • update: A bson_t <https://www.mongoc.org/libbson/current/bson_t.html> containing an update spec.
  • fields: An optional bson_t <https://www.mongoc.org/libbson/current/bson_t.html> containing the fields to return or NULL.
  • _remove: If the matching documents should be removed.
  • upsert: If an upsert should be performed.
  • _new: If the new version of the document should be returned.
  • reply: A maybe-NULL pointer to overwritable storage <https://www.mongoc.org/libbson/current/lifetimes.html> for a bson_t <https://www.mongoc.org/libbson/current/bson_t.html> to contain the results.
  • error: An optional location for a bson_error_t <> or NULL.

Update and return an object.

This is a thin wrapper around the findAndModify command. Either update or _remove arguments are required.

As of MongoDB 3.2, the mongoc_write_concern_t <> specified on the mongoc_collection_t <> will be used, if any.

reply is always initialized, and must be freed with bson_destroy() <https://www.mongoc.org/libbson/current/bson_destroy.html>.

On success, the output reply contains the full server reply to the findAndModify command. See the MongoDB Manual page for findAndModify <https://www.mongodb.com/docs/manual/reference/command/findAndModify/#output> for the expected server reply.

Errors are propagated via the error parameter.

If given invalid arguments or a server/network error occurs, returns false and sets error. Otherwise, succeeds and returns true. A write concern timeout or write concern error is considered a failure.

See also:

mongoc_collection_find_and_modify_with_opts() <>.



find-and-modify.c

#include <mongoc/mongoc.h>
#include <stdio.h>
int
main(void)
{
   mongoc_collection_t *collection;
   mongoc_client_t *client;
   const char *uri_string = "mongodb://127.0.0.1:27017/?appname=find-and-modify-example";
   mongoc_uri_t *uri;
   bson_error_t error;
   bson_t *query;
   bson_t *update;
   bson_t reply;
   char *str;
   mongoc_init();
   uri = mongoc_uri_new_with_error(uri_string, &error);
   if (!uri) {
      fprintf(stderr,
              "failed to parse URI:\n"
              "error message: %s\n",
              error.message);
      return EXIT_FAILURE;
   }
   client = mongoc_client_new_from_uri(uri);
   if (!client) {
      return EXIT_FAILURE;
   }
   mongoc_client_set_error_api(client, 2);
   collection = mongoc_client_get_collection(client, "test", "test");
   /*
    * Build our query, {"cmpxchg": 1}
    */
   query = BCON_NEW("cmpxchg", BCON_INT32(1));
   /*
    * Build our update. {"$set": {"cmpxchg": 2}}
    */
   update = BCON_NEW("$set", "{", "cmpxchg", BCON_INT32(2), "}");
   /*
    * Submit the findAndModify.
    */
   if (!mongoc_collection_find_and_modify(collection, query, NULL, update, NULL, false, false, true, &reply, &error)) {
      fprintf(stderr, "find_and_modify() failure: %s\n", error.message);
      return EXIT_FAILURE;
   }
   /*
    * Print the result as JSON.
    */
   str = bson_as_canonical_extended_json(&reply, NULL);
   printf("%s\n", str);
   bson_free(str);
   /*
    * Cleanup.
    */
   bson_destroy(query);
   bson_destroy(update);
   bson_destroy(&reply);
   mongoc_collection_destroy(collection);
   mongoc_uri_destroy(uri);
   mongoc_client_destroy(client);
   mongoc_cleanup();
   return EXIT_SUCCESS;
}


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