- MongoDB C Driver 1.13.1 »
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- mongoc_collection_t

# mongoc_collection_count()

## Deprecated

This function is deprecated and should not be used in new code. Use mongoc_collection_count_documents() or mongoc_collection_estimated_document_count() instead.

mongoc_collection_count_documents() has similar performance to calling mongoc_collection_count() with a non-NULL `query`, and is guaranteed to retrieve an accurate collection count. See migrating from deprecated count functions for details.

mongoc_collection_estimated_document_count() has the same performance as calling mongoc_collection_count() with a NULL `query`, but is not guaranteed to retrieve an accurate collection count.

## Synopsis

    int64_t
    mongoc_collection_count (mongoc_collection_t *collection,
                             mongoc_query_flags_t flags,
                             const bson_t *query,
                             int64_t skip,
                             int64_t limit,
                             const mongoc_read_prefs_t *read_prefs,
                             bson_error_t *error)
     BSON_GNUC_DEPRECATED_FOR (mongoc_collection_count_documents or
                               mongoc_collection_estimated_document_count);

## Parameters

- `collection`: A mongoc_collection_t.
- `flags`: A mongoc_query_flags_t.
- `query`: A `bson_t` containing the query.
- `skip`: A int64_t, zero to ignore.
- `limit`: A int64_t, zero to ignore.
- `read_prefs`: A mongoc_read_prefs_t or `NULL`.
- `error`: An optional location for a bson_error_t or `NULL`.

## Description

This function shall execute a count query on the underlying ‘collection’. The bson ‘query’ is not validated, simply passed along as appropriate to the server. As such, compatibility and errors should be validated in the appropriate server documentation.

For more information, see the query reference at the MongoDB website.

The mongoc_read_concern_t specified on the mongoc_collection_t will be used, if any. If `read_prefs` is NULL, the collection’s read preferences are used.

## Errors

Errors are propagated via the `error` parameter.

## Returns

-1 on failure, otherwise the number of documents counted.

## Example

    #include <bson/bson.h>
    #include <mongoc/mongoc.h>
    #include <stdio.h>

    static void
    print_query_count (mongoc_collection_t *collection, bson_t *query)
    {
       bson_error_t error;
       int64_t count;

       count = mongoc_collection_count (
          collection, MONGOC_QUERY_NONE, query, 0, 0, NULL, &error);

       if (count < 0) {
          fprintf (stderr, "Count failed: %s\n", error.message);
       } else {
          printf ("%" PRId64 " documents counted.\n", count);
       }
    }

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