nlohmann::basic_json::to_msgpack¶

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

Serializes a given JSON value j to a byte vector using the MessagePack serialization format. MessagePack 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 MessagePack serialization.
2. Writes the MessagePack 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. MessagePack 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 MessagePack
std::vector<std::uint8_t>v=json::to_msgpack(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;
}

0x820xa70x630x6f0x6d0x700x610x630x740xc30xa60x730x630x680x650x6d0x610x00

See also¶

• from_msgpack create a JSON value from an input in MessagePack format
• to_cbor create a CBOR 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.