mirror of
https://github.com/nlohmann/json.git
synced 2026-10-02 20:50:32 +00:00
Niels Lohmann
061c30310e
- API pages for basic_json_document and basic_json_view, one per member, and for the four aliases, each with an example - features/json_view.md: the problem the view solves, ownership and lifetime, what matches basic_json::parse() and what differs, and when to choose json, ordered_json, SAX, or the view - the examples show why one would use the view, not only how: borrowed vs. owned input, reading a few fields and materializing one subtree, reusing a document across many messages - registered in the mkdocs navigation, llms.txt, the docset, the exceptions page (out_of_range.416), architecture.md, the integration page, and the README; the yyjson credit is added to the README and license.md Signed-off-by: Niels Lohmann <mail@nlohmann.me>
1.2 KiB
1.2 KiB
nlohmann::basic_json_document::root
view_type root() const noexcept;
Returns a view of the root value of the document.
Return value
A view_type (i.e. #!cpp basic_json_view<BasicJsonType>) for the root value, or a
discarded view if the document is discarded.
Exception safety
No-throw guarantee: this function never throws exceptions.
Complexity
Constant.
Notes
root() is a cheap handle into the document's index, not a copy of anything; call it as often as needed. The
returned view is valid under the same conditions as any other view of the document -- see
Object inspection -- in particular, it is invalidated by the next
read() or shrink_to_fit() on this document.
Examples
??? example
```cpp
--8<-- "examples/basic_json_document__root.cpp"
```
Output:
```json
--8<-- "examples/basic_json_document__root.output"
```
See also
- is_discarded - return whether the last parse failed
- materialize - build the
BasicJsonTypevalue of a subtree
Version history
- Added in version 3.13.0.