JSON for Modern C++  3.9.1

◆ swap() [2/6]

void nlohmann::basic_json::swap ( binary_t other)
inline

Exchanges the contents of a JSON string with those of other. Does not invoke any move, copy, or swap operations on individual elements. All iterators and references remain valid. The past-the-end iterator is invalidated.

Parameters
[in,out]otherbinary to exchange the contents with
Exceptions
type_error.310when JSON value is not a string; example: "cannot use swap() with boolean"
Complexity
Constant.
Example
The example below shows how strings can be swapped with swap().
1 #include <iostream>
2 #include <nlohmann/json.hpp>
3 
4 using json = nlohmann::json;
5 
6 int main()
7 {
8  // create a binary value
9  json value = json::binary({1, 2, 3});
10 
11  // create a binary_t
12  json::binary_t binary = {{4, 5, 6}};
13 
14  // swap the object stored in the JSON value
15  value.swap(binary);
16 
17  // output the values
18  std::cout << "value = " << value << '\n';
19  std::cout << "binary = " << json(binary) << '\n';
20 }

Output (play with this example online):
value = {"bytes":[4,5,6],"subtype":null}
binary = {"bytes":[1,2,3],"subtype":null}
The example code above can be translated with
g++ -std=c++11 -Isingle_include doc/examples/swap__binary_t.cpp -o swap__binary_t 
Since
version 3.8.0

Definition at line 22528 of file json.hpp.

nlohmann::basic_json::value
ValueType value(const typename object_t::key_type &key, const ValueType &default_value) const
access specified object element with default value
Definition: json.hpp:20289
nlohmann::basic_json::binary_t
nlohmann::byte_container_with_subtype< BinaryType > binary_t
a type for a packed binary type
Definition: json.hpp:17398
nlohmann::basic_json::binary
static basic_json binary(const typename binary_t::container_type &init)
explicitly create a binary array (without subtype)
Definition: json.hpp:18167
nlohmann::json
basic_json<> json
default JSON class
Definition: json.hpp:2933