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. ^^
2 #include <nlohmann/json.hpp> 15 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 -Isingle_include doc/examples/basic_json__nullptr_t.cpp -o basic_json__nullptr_t
- Since
- version 1.0.0
Definition at line 13567 of file json.hpp.