json/api/basic_json/to_bson.md

nlohmann::basic_json::to_bson

// (1)
static std::vector<std::uint8_t> to_bson(const basic_json& j);

// (2)
static void to_bson(const basic_json& j, detail::output_adapter<std::uint8_t> o);
static void to_bson(const basic_json& j, detail::output_adapter<char> o);

BSON (Binary JSON) is a binary format in which zero or more ordered key/value pairs are stored as a single entity (a so-called document).

1. Returns a byte vector containing the BSON serialization.
2. Writes the BSON serialization to an output adapter.

The exact mapping and its limitations are described on a dedicated page.

Parameters

j (in)

JSON value to serialize

o (in)

output adapter to write serialization to

Return value

1. BSON serialization as a byte vector
2. (none)

Exception safety

Strong guarantee: if an exception is thrown, there are no changes in the JSON value.

Exceptions

• Throws type_error.317 if the top-level type of the JSON value is not an object; example: "to serialize to BSON, top-level type must be object, but is string"
• Throws out_of_range.409 if a key in the JSON object contains a null byte (code point U+0000); example: "BSON key cannot contain code point U+0000 (at byte 2)"

Complexity

Linear in the size of the JSON value j.

Examples

??? example

The example shows the serialization of a JSON value to a byte vector in BSON format.
 
```cpp
--8<-- "examples/to_bson.cpp"
```

Output:

```json
--8<-- "examples/to_bson.output"
```

See also

• from_bson create a JSON value from an input in BSON format
• to_cbor create a CBOR serialization of a JSON value
• to_msgpack create a MessagePack serialization of a JSON value
• to_ubjson create a UBJSON serialization of a JSON value
• to_bjdata create a BJData serialization of a JSON value

Version history

• Added in version 3.4.0.