allocator_type array array_t at at at at at at back back basic_json basic_json basic_json basic_json basic_json basic_json basic_json basic_json begin begin boolean_t cbegin cend clear const_iterator const_pointer const_reference const_reverse_iterator count crbegin crend detail::external_constructor diff difference_type dump emplace emplace_back empty end end erase erase erase erase exception find find flatten from_cbor from_msgpack front front get get get get get get_allocator get_ptr get_ptr get_ref get_ref insert insert insert insert insert insert invalid_iterator is_array is_boolean is_discarded is_null is_number is_number_float is_number_integer is_number_unsigned is_object is_primitive is_string is_structured iterator iterator_wrapper iterator_wrapper json_serializer max_size meta number_float_t number_integer_t number_unsigned_t object object_t operator value_t operator ValueType operator!= operator!= operator!= operator+= operator+= operator+= operator+= operator< operator< operator< operator<< operator<< operator<= operator<= operator<= operator= operator== operator== operator== operator> operator> operator> operator>= operator>= operator>= operator>> operator>> operator[] operator[] operator[] operator[] operator[] operator[] operator[] operator[] operator[] operator[] other_error out_of_range parse parse parse parse parse parse parse_error parse_event_t parser_callback_t patch pointer push_back push_back push_back push_back rbegin rbegin reference rend rend reverse_iterator size size_type string_t swap swap swap swap to_cbor to_msgpack type type_error type_name unflatten value value value value value_t value_type ~basic_json

max_size() 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> size_type nlohmann::basic_json::max_size ( ) const inlinenoexcept Returns the maximum number of elements a JSON value is able to hold due to system or library implementation limitations, i.e. std::distance(begin(), end()) for the JSON value. Returns The return value depends on the different types and is defined as follows: Value type return value null 0 (same as size()) boolean 1 (same as size()) string 1 (same as size()) number 1 (same as size()) object result of function object_t::max_size() array result of function array_t::max_size() Complexity Constant, as long as array_t and object_t satisfy the Container concept; that is, their max_size() functions have constant complexity. Requirements This function helps basic_json satisfying the Container requirements: The complexity is constant. Has the semantics of returning b.size() where b is the largest possible JSON value. Example The following code calls max_size() on the different value types. Note the output is implementation specific. #include "json.hpp" using json = nlohmann::json; int main() { // create JSON values json j_null; json j_boolean = true; json j_number_integer = 17; json j_number_float = 23.42; json j_object = {{"one", 1}, {"two", 2}}; json j_array = {1, 2, 4, 8, 16}; json j_string = "Hello, world"; // call max_size() std::cout << j_null.max_size() << '\n'; std::cout << j_boolean.max_size() << '\n'; std::cout << j_number_integer.max_size() << '\n'; std::cout << j_number_float.max_size() << '\n'; std::cout << j_object.max_size() << '\n'; std::cout << j_array.max_size() << '\n'; std::cout << j_string.max_size() << '\n'; } Output (play with this example online): 0 1 1 1 256204778801521550 1152921504606846975 1 The example code above can be translated with g++ -std=c++11 -Isrc doc/examples/max_size.cpp -o max_size See also size() – returns the number of elements Since version 1.0.0 Definition at line 5400 of file json.hpp.