Files
json/docs/mkdocs/docs/api/basic_json_view/is_string.md
Niels Lohmann 2d3492dccb Document json_document and json_view
- 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>
2026-09-30 15:07:21 +02:00

982 B

nlohmann::basic_json_view::is_string

bool is_string() const noexcept;

This function returns #!cpp true if and only if the value is a string.

Return value

#!cpp true if the type is a string, #!cpp false otherwise.

Exception safety

No-throw guarantee: this function never throws exceptions.

Complexity

Constant.

Examples

??? example

The example below classifies several parsed documents by the type of their root value, without materializing any
of them into a `BasicJsonType` value.

```cpp
--8<-- "examples/basic_json_view__type_predicates.cpp"
```

Output:

```json
--8<-- "examples/basic_json_view__type_predicates.output"
```

See also

Version history

  • Added in version 3.13.0.