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 = std::int64_t, class NumberUnsignedType = std::uint64_t, class NumberFloatType = double, template< typename U > class AllocatorType = std::allocator, template< typename T, typename SFINAE=void > class JSONSerializer = adl_serializer>
Create a null
JSON value. It either takes a null pointer as parameter (explicitly creating null
) or no parameter (implicitly creating null
). 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 and without a null pointer parameter.
14 std::cout << j1 <<
'\n' << j2 <<
'\n';
basic_json<> json
default JSON class
Output (play with this example online): null
null
The example code above can be translated withg++ -std=c++11 -Isrc doc/examples/basic_json__nullptr_t.cpp -o basic_json__nullptr_t
- Since
- version 1.0.0
Definition at line 1940 of file json.hpp.