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api/basic_json/exception.md

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+# <small>nlohmann::basic_json::</small>exception
+
+```cpp
+class exception : public std::exception;
+```
+
+This class is an extension of [`std::exception`](https://en.cppreference.com/w/cpp/error/exception) objects with a
+member `id` for exception ids. It is used as the base class for all exceptions thrown by the `basic_json` class. This
+class can hence be used as "wildcard" to catch exceptions, see example below.
+
+```mermaid
+classDiagram
+  direction LR
+  
+    class std_exception ["std::exception"] {
+        <<interface>>
+    }
+
+    class json_exception ["basic_json::exception"] {
+        +const int id
+        +const char* what() const
+    }
+    
+    class json_parse_error ["basic_json::parse_error"] {
+        +const std::size_t byte
+    }
+
+    class json_invalid_iterator ["basic_json::invalid_iterator"]
+    class json_type_error ["basic_json::type_error"]
+    class json_out_of_range ["basic_json::out_of_range"]
+    class json_other_error ["basic_json::other_error"]
+
+    std_exception <|-- json_exception
+    json_exception <|-- json_parse_error
+    json_exception <|-- json_invalid_iterator
+    json_exception <|-- json_type_error
+    json_exception <|-- json_out_of_range
+    json_exception <|-- json_other_error
+
+    style json_exception fill:#CCCCFF
+```
+
+Subclasses:
+
+- [`parse_error`](parse_error.md) for exceptions indicating a parse error
+- [`invalid_iterator`](invalid_iterator.md) for exceptions indicating errors with iterators
+- [`type_error`](type_error.md) for exceptions indicating executing a member function with a wrong type
+- [`out_of_range`](out_of_range.md) for exceptions indicating access out of the defined range
+- [`other_error`](other_error.md) for exceptions indicating other library errors
+
+## Member functions
+
+- **what** - returns explanatory string
+
+## Member variables
+
+- **id** - the id of the exception
+
+## Notes
+
+To have nothrow-copy-constructible exceptions, we internally use `std::runtime_error` which can cope with
+arbitrary-length error messages. Intermediate strings are built with static functions and then passed to the actual
+constructor.
+
+## Examples
+
+??? example
+
+    The following code shows how arbitrary library exceptions can be caught.
+    
+    ```cpp
+    --8<-- "examples/exception.cpp"
+    ```
+    
+    Output:
+    
+    ```json
+    --8<-- "examples/exception.output"
+    ```
+
+## See also
+
+[List of exceptions](../../home/exceptions.md)
+
+## Version history
+
+- Since version 3.0.0.