Class type_error

Defined in File json.hpp

Inheritance Relationships

Base Types

public nlohmann::detail::exception (Class exception)
public nlohmann::detail::exception (Class exception)

Class Documentation

class type_error : public nlohmann::detail::exception, public nlohmann::detail::exception 

exception indicating executing a member function with a wrong type

This exception is thrown in case of a type error; that is, a library function is executed on a JSON value whose type does not match the expected semantics.

Exceptions have ids 3xx.

name / id	example message	description
json.exception.type_error.301	cannot create object from initializer list	To create an object from an initializer list, the initializer list must consist only of a list of pairs whose first element is a string. When this constraint is violated, an array is created instead.
json.exception.type_error.302	type must be object, but is array	During implicit or explicit value conversion, the JSON type must be compatible to the target type. For instance, a JSON string can only be converted into string types, but not into numbers or boolean types.
json.exception.type_error.303	incompatible ReferenceType for get_ref, actual type is object	To retrieve a reference to a value stored in a basic_json object with get_ref, the type of the reference must match the value type. For instance, for a JSON array, the ReferenceType must be array_t &.
json.exception.type_error.304	cannot use at() with string	The at() member functions can only be executed for certain JSON types.
json.exception.type_error.305	cannot use operator[] with string	The operator[] member functions can only be executed for certain JSON types.
json.exception.type_error.306	cannot use value() with string	The value() member functions can only be executed for certain JSON types.
json.exception.type_error.307	cannot use erase() with string	The erase() member functions can only be executed for certain JSON types.
json.exception.type_error.308	cannot use push_back() with string	The push_back() and operator+= member functions can only be executed for certain JSON types.
json.exception.type_error.309	cannot use insert() with	The insert() member functions can only be executed for certain JSON types.
json.exception.type_error.310	cannot use swap() with number	The swap() member functions can only be executed for certain JSON types.
json.exception.type_error.311	cannot use emplace_back() with string	The emplace_back() member function can only be executed for certain JSON types.
json.exception.type_error.312	cannot use update() with string	The update() member functions can only be executed for certain JSON types.
json.exception.type_error.313	invalid value to unflatten	The unflatten function converts an object whose keys are JSON Pointers back into an arbitrary nested JSON value. The JSON Pointers must not overlap, because then the resulting value would not be well defined.
json.exception.type_error.314	only objects can be unflattened	The unflatten function only works for an object whose keys are JSON Pointers.
json.exception.type_error.315	values in object must be primitive	The unflatten function only works for an object whose keys are JSON Pointers and whose values are primitive.
json.exception.type_error.316	invalid UTF-8 byte at index 10: 0x7E	The dump function only works with UTF-8 encoded strings; that is, if you assign a `std::string` to a JSON value, make sure it is UTF-8 encoded.
json.exception.type_error.317	JSON value cannot be serialized to requested format	The dynamic type of the object cannot be represented in the requested serialization format (e.g. a raw `true` or `null` JSON object cannot be serialized to BSON)

@liveexample{The following code shows how a type_error exception can be caught.,type_error}

See also

- exception for the base class of the library exceptions

See also

- parse_error for exceptions indicating a parse error

See also

- invalid_iterator for exceptions indicating errors with iterators

See also

- out_of_range for exceptions indicating access out of the defined range

See also

- other_error for exceptions indicating other library errors

Since: version 3.0.0

Public Static Functions

static inline type_error create(int id_, const std::string &what_arg)

static inline type_error create(int id_, const std::string &what_arg)