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nlohmann
61 lines
1.8 KiB
Markdown
61 lines
1.8 KiB
Markdown
# <small>nlohmann::basic_json::</small>max_size
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```cpp
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size_type max_size() const noexcept;
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```
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Returns the maximum number of elements a JSON value is able to hold due to system or library implementation limitations,
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i.e. `std::distance(begin(), end())` for the JSON value.
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## Return value
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The return value depends on the different types and is defined as follows:
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| Value type | return value |
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|------------|-------------------------------------------|
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| null | `0` (same as [`size()`](size.md)) |
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| boolean | `1` (same as [`size()`](size.md)) |
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| string | `1` (same as [`size()`](size.md)) |
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| number | `1` (same as [`size()`](size.md)) |
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| binary | `1` (same as [`size()`](size.md)) |
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| object | result of function `object_t::max_size()` |
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| array | result of function `array_t::max_size()` |
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## Exception safety
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No-throw guarantee: this function never throws exceptions.
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## Complexity
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Constant, as long as [`array_t`](array_t.md) and [`object_t`](object_t.md) satisfy the
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[Container](https://en.cppreference.com/w/cpp/named_req/Container) concept; that is, their `max_size()` functions have
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constant complexity.
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## Notes
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This function does not return the maximal length of a string stored as JSON value -- it returns the maximal number of
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string elements the JSON value can store which is `1`.
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## Examples
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??? example
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The following code calls `max_size()` on the different value types.
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```cpp
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--8<-- "examples/max_size.cpp"
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```
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Output:
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```json
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--8<-- "examples/max_size.output"
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```
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Note the output is platform-dependent.
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## Version history
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- Added in version 1.0.0.
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- Extended to return `1` for binary types in version 3.8.0.
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