nlohmann::basic_json::to_cbor¶

// (1)
staticstd::vector<std::uint8_t>to_cbor(constbasic_json&j);
// (2)
staticvoidto_cbor(constbasic_json&j,detail::output_adapter<std::uint8_t>o);
staticvoidto_cbor(constbasic_json&j,detail::output_adapter<char>o);

Serializes a given JSON value j to a byte vector using the CBOR (Concise Binary Object Representation) serialization format. CBOR is a binary serialization format that aims to be more compact than JSON itself, yet more efficient to parse.

1. Returns a byte vector containing the CBOR serialization.
2. Writes the CBOR 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. CBOR serialization as a byte vector
2. (none)

Exception safety¶

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

Complexity¶

Linear in the size of the JSON value j.

Examples¶

#include<iostream>
#include<iomanip>
#include<nlohmann/json.hpp>
usingjson=nlohmann::json;
usingnamespacenlohmann::literals;
intmain()
{
// create a JSON value
jsonj=R"({"compact": true, "schema": 0})"_json;
// serialize it to CBOR
std::vector<std::uint8_t>v=json::to_cbor(j);
// print the vector content
for(auto&byte:v)
{
std::cout<<"0x"<<std::hex<<std::setw(2)<<std::setfill('0')<<(int)byte<<" ";
}
std::cout<<std::endl;
}

0xa20x670x630x6f0x6d0x700x610x630x740xf50x660x730x630x680x650x6d0x610x00

See also¶

• from_cbor create a JSON value from an input in CBOR format
• to_msgpack create a MessagePack serialization of a JSON value
• to_bson create a BSON 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 2.0.9.
• Compact representation of floating-point numbers added in version 3.8.0.