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 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.

Example

The following code shows the constructor with null pointer parameter.

#include <json.hpp>

using namespace nlohmann;

int main()
{
    // create a JSON null value
    json j(nullptr);

    // serialize the JSON null value
    std::cout << j << '\n';
}

Output:

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()