api/basic_json/max_size.md

# <small>nlohmann::basic_json::</small>max_size

```cpp
size_type max_size() const 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.
    
## Return value

The return value depends on the different types and is defined as follows:

| Value type | return value                              |
|------------|-------------------------------------------|
| null       | `0` (same as [`size()`](size.md))         |
| boolean    | `1` (same as [`size()`](size.md))         |
| string     | `1` (same as [`size()`](size.md))         |
| number     | `1` (same as [`size()`](size.md))         |
| binary     | `1` (same as [`size()`](size.md))         |
| object     | result of function `object_t::max_size()` |
| array      | result of function `array_t::max_size()`  |

## Exception safety

No-throw guarantee: this function never throws exceptions.

## Complexity

Constant, as long as [`array_t`](array_t.md) and [`object_t`](object_t.md) satisfy the
[Container](https://en.cppreference.com/w/cpp/named_req/Container) concept; that is, their `max_size()` functions have
constant complexity.

## Notes

This function does not return the maximal length of a string stored as JSON value -- it returns the maximal number of
string elements the JSON value can store which is `1`.

## Examples

??? example

    The following code calls `max_size()` on the different value types.
        
    ```cpp
    --8<-- "examples/max_size.cpp"
    ```
    
    Output:
    
    ```json
    --8<-- "examples/max_size.output"
    ```

    Note the output is platform-dependent.

## Version history

- Added in version 1.0.0.
- Extended to return `1` for binary types in version 3.8.0.