ceph/src/jaegertracing/opentelemetry-cpp/third_party/nlohmann-json/doc/mkdocs/docs/api/basic_json/flatten.md

   1 # <small>nlohmann::basic_json::</small>flatten
   2
   3 ```cpp
   4 basic_json flatten() const;
   5 ```
   6
   7 The function creates a JSON object whose keys are JSON pointers (see [RFC 6901](https://tools.ietf.org/html/rfc6901))
   8 and whose values are all primitive (see [`is_primitive()`](is_primitive.md) for more information). The original JSON
   9 value can be restored using the [`unflatten()`](unflatten.md) function.
  10
  11 ## Return value
  12
  13 an object that maps JSON pointers to primitive values
  14
  15 ## Exception safety
  16
  17 Strong exception safety: if an exception occurs, the original value stays intact.
  18
  19 ## Complexity
  20
  21 Linear in the size the JSON value.
  22
  23 ## Notes
  24
  25 Empty objects and arrays are flattened to `#!json null` and will not be reconstructed correctly by the
  26 [`unflatten()`](unflatten.md) function.
  27
  28 ## Examples
  29
  30 ??? example
  31
  32     The following code shows how a JSON object is flattened to an object whose keys consist of JSON pointers.
  33
  34     ```cpp
  35     --8<-- "examples/flatten.cpp"
  36     ```
  37
  38     Output:
  39
  40     ```json
  41     --8<-- "examples/flatten.output"
  42     ```
  43
  44 ## See also
  45
  46 - [unflatten](unflatten.md) the reverse function
  47
  48 ## Version history
  49
  50 - Added in version 2.0.0.