---
name: "bson_as_legacy_extended_json"
section: "3"
platform: "linux"
package: "libbson-doc"
version: "1.30.4-1+deb13u3"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/bson_as_legacy_extended_json"
---

# bson\_as\_legacy\_extended\_json(3)

## SYNOPSIS

```
char *
bson_as_legacy_extended_json (const bson_t *bson, size_t *length)
```

## PARAMETERS

- •

  **bson**: A *bson\_t*.

- •

  **length**: An optional location for the length of the resulting string.

## DESCRIPTION

*bson\_as\_legacy\_extended\_json()* encodes **bson** as a UTF-8 string using *libbson's Legacy Extended JSON*. This function is superseded by *bson\_as\_canonical\_extended\_json()* and *bson\_as\_relaxed\_extended\_json()*, which use the same *MongoDB Extended JSON format* as all other MongoDB drivers.

The caller is responsible for freeing the resulting UTF-8 encoded string by calling *bson\_free()* with the result.

If non-NULL, **length** will be set to the length of the result in bytes.

## RETURNS

If successful, a newly allocated UTF-8 encoded string and **length** is set.

Upon failure, NULL is returned.

## EXAMPLE

```
bson_t *b = BCON_NEW ("foo", BCON_INT32 (123));
char *str = bson_as_legacy_extended_json (b, NULL);
printf ("Legacy Extended JSON: %s\n", str);
// Prints:
// Legacy Extended JSON: { "foo" : 123 }
bson_free (str);
bson_destroy (b);
```

## AUTHOR

MongoDB, Inc

## COPYRIGHT

2009-present, MongoDB, Inc.