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* 🔥 consolidate documentation
* ♻️ overwork std specializations
* 🚚 move images files to mkdocs
* ♻️ fix URLs
* 🔧 tweak MkDocs configuration
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* 📝 document deprecations
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* 🚸 add examples
* 🚧 start adding documentation for macros
* 📝 add note for https://github.com/nlohmann/json/issues/874#issuecomment-1001699139
* 📝 overwork example handling
* 📝 fix Markdown tables

2021-12-29 13:41:01 +01:00

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nlohmann::basic_json::exception

class exception : public std::exception;

This class is an extension of std::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.

std::exception <|-- basic_json::exception
basic_json::exception <|-- basic_json::parse_error
basic_json::exception <|-- basic_json::invalid_iterator
basic_json::exception <|-- basic_json::type_error
basic_json::exception <|-- basic_json::out_of_range
basic_json::exception <|-- basic_json::other_error

interface std::exception {}

class basic_json::exception #FFFF00 {
    + const int id
    + const char* what() const
}

class basic_json::parse_error {
    + const std::size_t byte
}

Subclasses:

parse_error for exceptions indicating a parse error
invalid_iterator for exceptions indicating errors with iterators
type_error for exceptions indicating executing a member function with a wrong type
out_of_range for exceptions indicating access out of the defined range
other_error 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"
```

Version history

Since version 3.0.0.

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