JSON for Modern C++ 3.7.3

accept
accept
accept
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
basic_json
basic_json
begin
begin
binary
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detail::external_constructor
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emplace
emplace_back
empty
end
end
erase
erase
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erase
error_handler_t
exception
find
find
flatten
from_bson
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from_ubjson
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from_ubjson
front
front
get
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items
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iterator
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json_pointer
json_sax_t
json_serializer
max_size
merge_patch
meta
number_float_t
number_integer_t
number_unsigned_t
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operator ValueType
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~basic_json
| ## ◆ max_size()
size_type nlohmann::basic_json::max_size | ( |  | ) | const
| inline noexcept
  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()`)
  binary | `1` (same as `size()`)
  object | result of function `object_t::max_size()`
  array | result of function `array_t::max_size()`
  Example The following code calls `max_size()` on the different value types. Note the output is implementation specific. 1 #include <iostream> 2 #include <nlohmann/json.hpp> 3 4 using json = nlohmann::json; 5 6 int main() 7 { 8 // create JSON values 9 json j_null; 10 json j_boolean = true; 11 json j_number_integer = 17; 12 json j_number_float = 23.42; 13 json j_object = {{"one", 1}, {"two", 2}}; 14 json j_array = {1, 2, 4, 8, 16}; 15 json j_string = "Hello, world"; 16 17 // call max_size() 18 std::cout << j_null.max_size() << '\n'; 19 std::cout << j_boolean.max_size() << '\n'; 20 std::cout << j_number_integer.max_size() << '\n'; 21 std::cout << j_number_float.max_size() << '\n'; 22 std::cout << j_object.max_size() << '\n'; 23 std::cout << j_array.max_size() << '\n'; 24 std::cout << j_string.max_size() << '\n'; 25 } 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 -Isingle_include doc/examples/max_size.cpp -o 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. Iterator validity No changes. Exception safety No-throw guarantee: this function never throws exceptions. 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. See also size() – returns the number of elements Since version 1.0.0 Definition at line 20860 of file json.hpp.

nlohmann::json
basic_json<> json
default JSON class
Definition: json.hpp:2774