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2d3492dccb
- 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>
1.1 KiB
1.1 KiB
nlohmann::basic_json_document::is_discarded
bool is_discarded() const noexcept;
Returns whether the document holds no value, either because it was default-constructed or because the last call to
parse(), parse_copy(), or read() failed with allow_exceptions set to
#!cpp false.
Return value
#!cpp true if the document is discarded, #!cpp false otherwise.
Exception safety
No-throw guarantee: this function never throws exceptions.
Complexity
Constant.
Notes
When the document is discarded, root() returns a discarded view (its
is_discarded() is also #!cpp true).
Examples
??? example
```cpp
--8<-- "examples/basic_json_document__is_discarded.cpp"
```
Output:
```json
--8<-- "examples/basic_json_document__is_discarded.output"
```
See also
- parse - deserialize from a compatible input
- is_discarded (basic_json_view) - return whether a view is invalid
Version history
- Added in version 3.13.0.