JSON for Modern C++  2.0.0
template<template< typename U, typename V, typename...Args > class ObjectType = std::map, template< typename U, typename...Args > class ArrayType = std::vector, class StringType = std::string, class BooleanType = bool, class NumberIntegerType = int64_t, class NumberUnsignedType = uint64_t, class NumberFloatType = double, template< typename U > class AllocatorType = std::allocator>
nlohmann::basic_json::basic_json ( std::nullptr_t  )
inlinenoexcept

Create a null JSON value. This is the explicitly version of the null value constructor as it takes a null pointer as parameter. It allows to create null values by explicitly assigning a nullptr to a JSON value. The passed null pointer itself is not read – it is only used to choose the right constructor.

Complexity
Constant.
Exception safety
No-throw guarantee: this constructor never throws exceptions.
Example
The following code shows the constructor with null pointer parameter.
1 #include <json.hpp>
2 
3 using json = nlohmann::json;
4 
5 int main()
6 {
7  // create a JSON null value
8  json j(nullptr);
9 
10  // serialize the JSON null value
11  std::cout << j << '\n';
12 }
basic_json<> json
default JSON class
Definition: json.hpp:8653
Output (play with this example online):
null
The example code above can be translated with
g++ -std=c++11 -Isrc doc/examples/basic_json__nullptr_t.cpp -o basic_json__nullptr_t 
See also
basic_json() – default constructor (implicitly creating a null value)
Since
version 1.0.0

Definition at line 984 of file json.hpp.