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Author SHA1 Message Date
Niels Lohmann d2e05c8b45 Fix rollback of pointer operator[] for unusual object and string types
Follow-up to the strong exception guarantee of the non-const
operator[](json_pointer):

- get_unchecked_create assumed that emplace() always inserts the key that
  the walk did not find. For object types whose lookup and emplace()
  disagree (e.g. a copied fifo_map), nothing was inserted, the rollback
  erased the existing member, and the walk continued with a value of the
  wrong type (assertion, type_error.305, or a crash). It now checks the
  result of emplace(), arms the rollback only if a key was inserted, and
  otherwise continues the walk with the member found, as basic_json's
  operator[] does: such pointers throw out_of_range.404 and leave the value
  unchanged, as before the strong guarantee.
- The rollback erased the inserted key by key, which converts string_t to
  object_t::key_type and may allocate inside a noexcept function
  (std::terminate on bad_alloc with custom key types). It now erases by the
  iterator emplace() returned, and shrinks a grown array with erase() at
  the end instead of resize(). The documentation states the remaining
  requirement for custom template parameters.
- Creating values no longer calls string_t::begin(), so the non-const
  operator[](json_pointer) compiles with string types that lack it (as the
  alternative string type of the tests).
- Correct the @throw lists of get_unchecked and get_unchecked_create.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-26 17:13:52 +01:00
Niels Lohmann d1566fe9e8 Make the strongly exception-safe pointer operator[] faster than before
The previous commit made get_unchecked strongly exception safe but slower
with GCC 16 when it creates values (up to +6 % instructions for appending
with "-"). This restructures it so that no benchmark row is slower than
before the strong guarantee, with GCC 16, Clang 22 and Apple Clang.

- get_unchecked walks existing values in one loop that inserts nothing.
  The last reference token is resolved in that walk: "-" appends with
  emplace_back(), an index grows the array with operator[], and a missing
  key is inserted with emplace_hint() at the position the walk's
  lower_bound() found, so the key is searched once.
- With std::less<string_t> or std::less<> as comparator, the walk checks
  the key at the lower bound for equality instead of equivalence, which is
  the same for these comparators and cheaper.
- get_unchecked_create (not inlined) handles all other changes. Its guard
  swaps a null value with a fresh null value instead of copying it and
  reverts the change in a non-inlined function, so a successful call pays
  one compare for it. As every null value converted afterwards is a fresh
  one, it is converted in place instead of assigning a new array or object.
- Keys are added to new objects with emplace(), which also replaces the
  basic_json::operator[] call for ordered_json.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-26 17:13:52 +01:00
Niels Lohmann 3351a8795b Keep the value unchanged when operator[] with a JSON pointer throws
The non-const operator[](json_pointer) is documented with strong exception
safety, but get_unchecked created intermediate values while walking the
pointer and kept them when a later reference token failed, e.g.
json j; j["/a/99999999999999999999999"_json_pointer] threw 404 and left
{"a":[]}; padding an existing array or appending with "-" behaved alike,
and so did std::length_error/std::bad_alloc from a huge index.

get_unchecked now only walks existing values up to the last reference
token. The last token's key insertion or array growth is strongly
exception safe by itself. Any other change goes through
get_unchecked_create, which records the one change it makes to an existing
value (null converted, key inserted, array grown) in a RAII guard and
reverts it if a later step throws; everything else it creates lies below
that change. The guard needs no try/catch, so JSON_NOEXCEPTION builds are
unaffected. Successful calls create the same values as before.

Docs: state the guarantee in the exceptions list and version history of
operator[], fix the complexity of the pointer overloads of operator[] and
at, and warn that padding arrays up to an untrusted index allocates memory
proportional to the index (operator[].md, untrusted_input.md).

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-26 17:13:52 +01:00
424 changed files with 4161 additions and 11169 deletions

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@@ -30,7 +30,7 @@ class (either explicitly or via the conversion operators).
## Return value
1. (none) — the converted value is written to the output parameter `val`.
1. (none) -- the converted value is written to the output parameter `val`.
2. the JSON value `j` converted to `TargetType`
## Examples
@@ -67,9 +67,7 @@ class (either explicitly or via the conversion operators).
## See also
- [`to_json`](to_json.md) - convert a C++ value to JSON
- [Arbitrary Type Conversions](../../features/arbitrary_types.md) - write your own `from_json` and `to_json` functions
- [Converting values](../../features/conversions.md) - overview of `get`, `get_to` and implicit conversions
- [to_json](to_json.md)
## Version history
+4 -4
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@@ -33,10 +33,10 @@ struct adl_serializer {
## See also
- [Arbitrary type conversions](../../features/arbitrary_types.md) - how to make your types convertible
- [`get`](../basic_json/get.md) - / [`get_to`](../basic_json/get_to.md) - convert a JSON value to a C++ type
- [`basic_json`](../basic_json/basic_json.md) - construct a JSON value from a C++ value
- [`NLOHMANN_DEFINE_TYPE_INTRUSIVE`](../macros/nlohmann_define_type_intrusive.md) - generate the conversion functions for a type
- [Specializing enum conversion](../../features/enum_conversion.md) - serializing enums as JSON strings
- [**get**](../basic_json/get.md) / [**get_to**](../basic_json/get_to.md) - convert a JSON value to a C++ type
- [**basic_json**](../basic_json/basic_json.md) - construct a JSON value from a C++ value
- [**NLOHMANN_DEFINE_TYPE_INTRUSIVE**](../macros/nlohmann_define_type_intrusive.md) - generate the conversion functions for a type
- [Specializing enum conversion](../../features/enum_conversion.md)
## Version history
@@ -36,9 +36,7 @@ This function is usually called by the constructors of the [basic_json](../basic
## See also
- [`from_json`](from_json.md) - convert JSON to a C++ value
- [Arbitrary Type Conversions](../../features/arbitrary_types.md) - write your own `from_json` and `to_json` functions
- [Converting values](../../features/conversions.md) - overview of `get`, `get_to` and implicit conversions
- [from_json](from_json.md)
## Version history
+3 -8
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@@ -148,20 +148,15 @@ outside of a string, invalid) byte; see the [FAQ entry](../../home/faq.md#nul-by
## See also
- [`parse`](parse.md) - deserialize from a compatible input
- [`sax_parse`](sax_parse.md) - parse input using the SAX interface
- [`operator>>`](../operator_gtgt.md) - deserialize from stream
- [parse](parse.md) - deserialize from a compatible input
- [sax_parse](sax_parse.md) - parse input using the SAX interface
- [operator>>](../operator_gtgt.md) - deserialize from stream
- [`JSON_STRICT_NUL_HANDLING`](../macros/json_strict_nul_handling.md) - opt in to rejecting a NUL byte in the input
instead of treating it as end of input
- [`JSON_DISABLE_STREAM_BULK_SCAN`](../macros/json_disable_stream_bulk_scan.md) - read a `std::istream` one character
at a time
- [`JSON_DISABLE_UNLOCKED_FILE_IO`](../macros/json_disable_unlocked_file_io.md) - read a `FILE*` with the locking stdio
functions
- [Parsing](../../features/parsing/index.md) - overview of the parsing functions
- [Comments](../../features/comments.md) - ignore `//` and `/* */` comments while parsing
- [Trailing Commas](../../features/trailing_commas.md) - accept trailing commas in arrays and objects
- [Parsing and Exceptions](../../features/parsing/parse_exceptions.md) - handling parse errors and locating them in the input
- [Parsing Untrusted Input](../../features/parsing/untrusted_input.md) - limits and checks for input you do not control
## Version history
+2 -2
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@@ -29,9 +29,9 @@ Linear in the size of `init`.
This function is only needed to express two edge cases that cannot be realized with the initializer list constructor
([`basic_json(initializer_list_t, bool, value_t)`](basic_json.md)). These cases are:
1. creating an array whose elements are all pairs whose first element is a string — in this case, the initializer list
1. creating an array whose elements are all pairs whose first element is a string -- in this case, the initializer list
constructor would create an object, taking the first elements as keys
2. creating an empty array — passing the empty initializer list to the initializer list constructor yields an empty
2. creating an empty array -- passing the empty initializer list to the initializer list constructor yields an empty
object
## Examples
+4 -6
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@@ -69,12 +69,10 @@ Arrays are stored as pointers in a `basic_json` type. That is, for any access to
## See also
- [`object_t`](object_t.md) - the type used to store JSON objects
- [`binary_t`](binary_t.md) - the type used to store binary values
- [`is_array`](is_array.md) - checks whether the JSON value is an array
- [`max_size`](max_size.md) - returns the maximum possible number of elements
- [Types](../../features/types/index.md) - how arrays are stored
- [Template Parameter Requirements](../../features/types/template_parameters.md) - requirements on the `ArrayType` template parameter
- [object_t](object_t.md) the type used to store JSON objects
- [binary_t](binary_t.md) the type used to store binary values
- [is_array](is_array.md) checks whether the JSON value is an array
- [max_size](max_size.md) returns the maximum possible number of elements
## Version history
@@ -46,8 +46,7 @@ The function is equivalent to `static_cast<json_base_class_t&>(j)` (or `static_c
## See also
- [`json_base_class_t`](json_base_class_t.md) - type of the custom base class
- [Template Parameter Requirements](../../features/types/template_parameters.md) - requirements on the `CustomBaseClass` template parameter
- [json_base_class_t](json_base_class_t.md) - type of the custom base class
## Version history
+6 -7
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@@ -90,7 +90,8 @@ Strong exception safety: if an exception occurs, the original value stays intact
1. Constant.
2. Logarithmic in the size of the container.
3. Logarithmic in the size of the container.
4. Logarithmic in the size of the container.
4. Linear in the number of reference tokens of `ptr`; for each of them, logarithmic in the size of the object, or
constant for an array.
## Notes
@@ -230,12 +231,10 @@ Strong exception safety: if an exception occurs, the original value stays intact
## See also
- [Checked access](../../features/element_access/checked_access.md) - element access with range checking
- [`operator[]`](operator%5B%5D.md) - unchecked access by reference
- [`value`](value.md) - access with default value
- [`basic_json_view::at`](../basic_json_view/at.md) - the same access on a zero-copy view
- [Element Access](../../features/element_access/index.md) - overview of all ways to access elements
- [JSON Pointer](../../features/json_pointer.md) - access nested values with a pointer
- documentation on [checked access](../../features/element_access/checked_access.md)
- [`operator[]`](operator%5B%5D.md) for unchecked access by reference
- [`value`](value.md) for access with default value
- [basic_json_view::at](../basic_json_view/at.md) - the same access on a zero-copy view
## Version history
+2 -3
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@@ -57,9 +57,8 @@ Constant.
## See also
- [`front`](front.md) - to access the first element
- [`basic_json_view::back`](../basic_json_view/back.md) - the same access on a zero-copy view
- [Element Access](../../features/element_access/index.md) - overview of all ways to access elements
- [front](front.md) to access the first element
- [basic_json_view::back](../basic_json_view/back.md) - the same access on a zero-copy view
## Version history
+10 -14
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@@ -52,7 +52,7 @@ basic_json(basic_json&& other) noexcept;
The postcondition of this constructor can be restored by calling [`clear()`](clear.md).
2. Create a `#!json null` JSON value. It either takes a null pointer as parameter (explicitly creating `#!json null`)
or no parameter (implicitly creating `#!json null`). The passed null pointer itself is not read — it is only used to
or no parameter (implicitly creating `#!json null`). The passed null pointer itself is not read -- it is only used to
choose the right constructor.
3. This is a "catch all" constructor for all compatible JSON types; that is, types for which a `to_json()` method
@@ -113,22 +113,19 @@ basic_json(basic_json&& other) noexcept;
```mermaid
flowchart TD
A(["initializer_list init"]) --> B{{"empty, or every element is a 2-element<br/>array whose first element is a string?"}}
B -->|"yes"| C{{"type_deduction"}}
B -->|"no"| D{{"type_deduction"}}
A(["initializer_list init"]) --> B{"empty, or every element is a 2-element<br/>array whose first element is a string?"}
B -->|"yes"| C{"type_deduction"}
B -->|"no"| D{"type_deduction"}
C -->|"true"| OBJ["create object"]
C -->|"false"| E{{"manual_type"}}
C -->|"false"| E{"manual_type"}
E -->|"object"| OBJ
E -->|"array"| ARR["create array"]
D -->|"true"| ARR
D -->|"false"| F{{"manual_type"}}
D -->|"false"| F{"manual_type"}
F -->|"array"| ARR
F -->|"object"| ERR["throw type_error.301"]
```
<p class="nj-caption" markdown>Decision flow for an initializer list: hexagons are checks, edge labels are their
outcomes, and rectangles are the resulting value or exception.</p>
The rules aim to create the best fit between a C++ initializer list and JSON values. The rationale is as follows:
1. The empty initializer list is written as `#!cpp {}` which is exactly an empty JSON object.
@@ -476,13 +473,12 @@ basic_json(basic_json&& other) noexcept;
## See also
- [`array`](array.md) - create a JSON array value, forcing array creation from an initializer list even when it looks like
- [array](array.md) create a JSON array value, forcing array creation from an initializer list even when it looks like
an object
- [`object`](object.md) - create a JSON object value, forcing object creation from an initializer list
- [`binary`](binary.md) - create a JSON binary array value
- [`operator=`](operator=.md) - copy assignment operator
- [object](object.md) create a JSON object value, forcing object creation from an initializer list
- [binary](binary.md) create a JSON binary array value
- [operator=](operator=.md) copy assignment operator
- [Creating JSON values](../../features/creating_values.md) - the article on creating JSON values
- [Converting values](../../features/conversions.md) - which C++ types can be converted
## Version history
+6 -11
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@@ -7,12 +7,7 @@ const_iterator begin() const noexcept;
Returns an iterator to the first element.
<div class="nj-fig-wrap" markdown>
--8<-- "images/range-begin-end.svg"
</div>
<p class="nj-caption" markdown>`begin()` points to the first element and `end()` to the position after the last element;
the dashed cell is the past-the-last position, which must not be dereferenced.</p>
![Illustration from cppreference.com](../../images/range-begin-end.svg)
## Return value
@@ -44,12 +39,12 @@ Constant.
## See also
- [`end`](end.md) - returns an iterator to one past the last element
- [`cbegin`](cbegin.md) - returns a const iterator to the first element
- [`rbegin`](rbegin.md) - returns a reverse iterator to the last element
- [`items`](items.md) - returns an iteration proxy to access keys and values during range-based for loops
- [end](end.md) returns an iterator to one past the last element
- [cbegin](cbegin.md) returns a const iterator to the first element
- [rbegin](rbegin.md) returns a reverse iterator to the last element
- [items](items.md) returns an iteration proxy to access keys and values during range-based for loops
- [Iterators](../../features/iterators.md) - the article on iterators
- [`basic_json_view::begin`](../basic_json_view/begin.md) - the same iteration on a zero-copy view (in document order,
- [basic_json_view::begin](../basic_json_view/begin.md) - the same iteration on a zero-copy view (in document order,
not sorted by key)
## Version history
+4 -5
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@@ -63,11 +63,10 @@ initialization of a binary array type, for backwards compatibility and so it doe
## See also
- [Binary formats](../../features/binary_formats/index.md) - formats that can store binary values
- [`binary_t`](binary_t.md) - type for binary values
- [`get_binary`](get_binary.md) - get a reference to the stored binary value
- [`is_binary`](is_binary.md) - return whether the value is binary
- [`byte_container_with_subtype`](../byte_container_with_subtype/index.md) - container for binary values with subtype
- [binary_t](binary_t.md) type for binary values
- [get_binary](get_binary.md) get a reference to the stored binary value
- [is_binary](is_binary.md) return whether the value is binary
- [byte_container_with_subtype](../byte_container_with_subtype/index.md) container for binary values with subtype
- [Binary Values](../../features/binary_values.md) - the article on binary values
## Version history
+2 -4
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@@ -41,7 +41,7 @@ represent a byte array in modern C++.
[`byte_container_with_subtype`](../byte_container_with_subtype/index.md) derives directly from it. Its
`value_type` must additionally be exactly one byte wide (e.g., `std::uint8_t`/`char`/`std::byte`): the binary
serializers (CBOR, MessagePack, BSON, UBJSON) read and write the container's raw bytes via
`reinterpret_cast`, which is only correct for byte-sized elements — a container like
`reinterpret_cast`, which is only correct for byte-sized elements -- a container like
`#!cpp std::vector<std::intptr_t>` will not work as `BinaryType`. The elements must be stored contiguously, and
the binary readers additionally require `resize()` and `operator[]`. See
[Template Parameter Requirements](../../features/types/template_parameters.md#binarytype) for the full list.
@@ -117,9 +117,7 @@ type `#!cpp binary_t*` must be dereferenced.
## See also
- [Binary values](../../features/binary_values.md) - how binary values and subtypes are handled
- [Binary formats](../../features/binary_formats/index.md) - formats that can store binary values
- [`byte_container_with_subtype`](../byte_container_with_subtype/index.md) - container type used by binary values
- [byte_container_with_subtype](../byte_container_with_subtype/index.md)
## Version history
+1 -3
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@@ -47,9 +47,7 @@ Boolean values are stored directly inside a `basic_json` type.
## See also
- [`is_boolean`](is_boolean.md) - checks whether the JSON value is a boolean
- [Types](../../features/types/index.md) - how booleans are stored
- [Template Parameter Requirements](../../features/types/template_parameters.md) - requirements on the `BooleanType` template parameter
- [is_boolean](is_boolean.md) checks whether the JSON value is a boolean
## Version history
+5 -10
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@@ -6,12 +6,7 @@ const_iterator cbegin() const noexcept;
Returns an iterator to the first element.
<div class="nj-fig-wrap" markdown>
--8<-- "images/range-begin-end.svg"
</div>
<p class="nj-caption" markdown>`cbegin()` points to the first element, like `begin()`, and `end()` to the position after
the last element; the dashed cell is the past-the-last position, which must not be dereferenced.</p>
![Illustration from cppreference.com](../../images/range-begin-end.svg)
## Return value
@@ -43,11 +38,11 @@ Constant.
## See also
- [`begin`](begin.md) - returns an iterator to the first element
- [`cend`](cend.md) - returns a const iterator to one past the last element
- [`crbegin`](crbegin.md) - returns a const reverse iterator to the last element
- [begin](begin.md) returns an iterator to the first element
- [cend](cend.md) returns a const iterator to one past the last element
- [crbegin](crbegin.md) returns a const reverse iterator to the last element
- [Iterators](../../features/iterators.md) - the article on iterators
- [`basic_json_view::cbegin`](../basic_json_view/cbegin.md) - the same iteration on a zero-copy view
- [basic_json_view::cbegin](../basic_json_view/cbegin.md) - the same iteration on a zero-copy view
## Version history
@@ -40,9 +40,8 @@ store
## See also
- [Binary values](../../features/binary_values.md) - how binary values and subtypes are handled
- [`from_cbor`](from_cbor.md) - deserializes a JSON value from CBOR
- [`input_format_t`](input_format_t.md) - the enumeration of supported input formats
- [from_cbor](from_cbor.md) deserializes a JSON value from CBOR
- [input_format_t](input_format_t.md) the enumeration of supported input formats
- [CBOR](../../features/binary_formats/cbor.md) - the article on the CBOR format
## Version history
+5 -10
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@@ -6,12 +6,7 @@ const_iterator cend() const noexcept;
Returns an iterator to one past the last element.
<div class="nj-fig-wrap" markdown>
--8<-- "images/range-begin-end.svg"
</div>
<p class="nj-caption" markdown>`cend()` points to the position after the last element, like `end()`, and `begin()` to
the first element; the dashed cell is the past-the-last position, which must not be dereferenced.</p>
![Illustration from cppreference.com](../../images/range-begin-end.svg)
## Return value
@@ -43,11 +38,11 @@ Constant.
## See also
- [`end`](end.md) - returns an iterator to one past the last element
- [`cbegin`](cbegin.md) - returns a const iterator to the first element
- [`crend`](crend.md) - returns a const reverse iterator to one before the first element
- [end](end.md) returns an iterator to one past the last element
- [cbegin](cbegin.md) returns a const iterator to the first element
- [crend](crend.md) returns a const reverse iterator to one before the first element
- [Iterators](../../features/iterators.md) - the article on iterators
- [`basic_json_view::cend`](../basic_json_view/cend.md) - the same iteration on a zero-copy view
- [basic_json_view::cend](../basic_json_view/cend.md) - the same iteration on a zero-copy view
## Version history
+2 -3
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@@ -54,9 +54,8 @@ All iterators, pointers, and references related to this container are invalidate
## See also
- [`erase`](erase.md) - removes elements from a JSON value
- [`empty`](empty.md) - checks whether the JSON value has no elements
- [Modifying values](../../features/modifying_values.md) - the article on modifying values
- [erase](erase.md) removes elements from a JSON value
- [empty](empty.md) checks whether the JSON value has no elements
## Version history
+3 -4
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@@ -141,10 +141,9 @@ Strong exception safety: if an exception occurs, the original value stays intact
## See also
- [`find`](find.md) - find a value in an object
- [`count`](count.md) - returns the number of occurrences of a key
- [`basic_json_view::contains`](../basic_json_view/contains.md) - the same check on a zero-copy view
- [Element Access](../../features/element_access/index.md#does-this-key-exist) - how to test whether a key exists
- [find](find.md) find a value in an object
- [count](count.md) returns the number of occurrences of a key
- [basic_json_view::contains](../basic_json_view/contains.md) - the same check on a zero-copy view
## Version history
+3 -4
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@@ -85,10 +85,9 @@ Logarithmic in the size of the JSON object.
## See also
- [`find`](find.md) - find a value in an object
- [`contains`](contains.md) - checks whether a key exists
- [`basic_json_view::count`](../basic_json_view/count.md) - the same check on a zero-copy view
- [Element Access](../../features/element_access/index.md#does-this-key-exist) - how to test whether a key exists
- [find](find.md) find a value in an object
- [contains](contains.md) checks whether a key exists
- [basic_json_view::count](../basic_json_view/count.md) - the same check on a zero-copy view
## Version history
+4 -10
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@@ -6,13 +6,7 @@ const_reverse_iterator crbegin() const noexcept;
Returns an iterator to the reverse-beginning; that is, the last element.
<div class="nj-fig-wrap" markdown>
--8<-- "images/range-rbegin-rend.svg"
</div>
<p class="nj-caption" markdown>`crbegin()` points to the last element, like `rbegin()`, and `rend()` to the position
before the first element. The upper row is the reversed sequence and the lower row the forward sequence; dashed arrows
link each reverse iterator to the forward iterator it stores, and dashed cells are past-the-last positions.</p>
![Illustration from cppreference.com](../../images/range-rbegin-rend.svg)
## Return value
@@ -44,9 +38,9 @@ Constant.
## See also
- [`crend`](crend.md) - returns a const reverse iterator to one before the first element
- [`rbegin`](rbegin.md) - returns a reverse iterator to the last element
- [`cbegin`](cbegin.md) - returns a const iterator to the first element
- [crend](crend.md) returns a const reverse iterator to one before the first element
- [rbegin](rbegin.md) returns a reverse iterator to the last element
- [cbegin](cbegin.md) returns a const iterator to the first element
- [Iterators](../../features/iterators.md) - the article on iterators
## Version history
+4 -10
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@@ -7,13 +7,7 @@ const_reverse_iterator crend() const noexcept;
Returns an iterator to the reverse-end; that is, one before the first element. This element acts as a placeholder,
attempting to access it results in undefined behavior.
<div class="nj-fig-wrap" markdown>
--8<-- "images/range-rbegin-rend.svg"
</div>
<p class="nj-caption" markdown>`crend()` points to the position before the first element, like `rend()`, and `rbegin()`
to the last element. The upper row is the reversed sequence and the lower row the forward sequence; dashed arrows link
each reverse iterator to the forward iterator it stores, and dashed cells are past-the-last positions.</p>
![Illustration from cppreference.com](../../images/range-rbegin-rend.svg)
## Return value
@@ -45,9 +39,9 @@ Constant.
## See also
- [`crbegin`](crbegin.md) - returns a const reverse iterator to the last element
- [`rend`](rend.md) - returns a reverse iterator to one before the first element
- [`cend`](cend.md) - returns a const iterator to one past the last element
- [crbegin](crbegin.md) returns a const reverse iterator to the last element
- [rend](rend.md) returns a reverse iterator to one before the first element
- [cend](cend.md) returns a const iterator to one past the last element
- [Iterators](../../features/iterators.md) - the article on iterators
## Version history
@@ -32,10 +32,8 @@ The actual comparator used depends on [`object_t`](object_t.md) and can be obtai
## See also
- [`object_comparator_t`](object_comparator_t.md) - the comparator actually used by `object_t`
- [`object_t`](object_t.md) - the type used to store JSON objects
- [Template Parameter Requirements](../../features/types/template_parameters.md) - requirements on the `ObjectType` template parameter
- [Object order](../../features/object_order.md) - preserve the insertion order of keys
- [object_comparator_t](object_comparator_t.md) the comparator actually used by `object_t`
- [object_t](object_t.md) the type used to store JSON objects
## Version history
+5 -6
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@@ -92,12 +92,11 @@ operations times the length of their paths, so a small change deep inside a valu
## See also
- [RFC 6902 (JSON Patch)](https://tools.ietf.org/html/rfc6902) - specification of JSON Patch
- [`patch`](patch.md) - applies a JSON Patch
- [`patch_inplace`](patch_inplace.md) - applies a JSON Patch in place
- [`merge_patch`](merge_patch.md) - applies a JSON Merge Patch
- [`merge_diff`](merge_diff.md) - creates a diff as a JSON Merge Patch
- [JSON Patch and Diff](../../features/json_patch.md) - the article on JSON Patch
- [RFC 6902 (JSON Patch)](https://tools.ietf.org/html/rfc6902)
- [patch](patch.md) applies a JSON Patch
- [patch_inplace](patch_inplace.md) applies a JSON Patch in place
- [merge_patch](merge_patch.md) applies a JSON Merge Patch
- [merge_diff](merge_diff.md) creates a diff as a JSON Merge Patch
## Version history
+3 -3
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@@ -89,9 +89,9 @@ Binary values are serialized as an object containing two keys:
## See also
- [`to_string`](to_string.md) - returns a string representation of a JSON value
- [`operator<<`](../operator_ltlt.md) - serialize to stream
- [`basic_json_view::dump`](../basic_json_view/dump.md) - the corresponding function of `basic_json_view`, serializing
- [to_string](to_string.md) returns a string representation of a JSON value
- [operator<<](../operator_ltlt.md) serialize to stream
- [`basic_json_view::dump`](../basic_json_view/dump.md) the corresponding function of `basic_json_view`, serializing
directly from a flat index without building a `basic_json` value
- [Serialization](../../features/serialization.md) - the serialization article
+2 -2
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@@ -63,8 +63,8 @@ Logarithmic in the size of the container, O(log(`size()`)).
## See also
- [`emplace_back`](emplace_back.md) - add a value to an array
- [`insert`](insert.md) - add values to an array/object
- [emplace_back](emplace_back.md) add a value to an array
- [insert](insert.md) add values to an array/object
- [Modifying values](../../features/modifying_values.md) - the article on modifying values
## Version history
@@ -61,8 +61,8 @@ Amortized constant.
## See also
- [`operator+=`](operator+=.md) - add a value to an array/object
- [`push_back`](push_back.md) - add a value to an array/object
- [operator+=](operator+=.md) add a value to an array/object
- [push_back](push_back.md) add a value to an array/object
- [Modifying values](../../features/modifying_values.md) - the article on modifying values
## Version history
+4 -4
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@@ -41,7 +41,7 @@ bool empty() const noexcept
## Notes
This function does not return whether a string stored as JSON value is empty — it returns whether the JSON container
This function does not return whether a string stored as JSON value is empty -- it returns whether the JSON container
itself is empty which is `#!cpp false` in the case of a string.
## Examples
@@ -62,9 +62,9 @@ itself is empty which is `#!cpp false` in the case of a string.
## See also
- [`size`](size.md) - returns the number of elements
- [`clear`](clear.md) - clears the content and resets the value to the default value
- [`basic_json_view::empty`](../basic_json_view/empty.md) - the same check on a zero-copy view
- [size](size.md) returns the number of elements
- [clear](clear.md) clears the content and resets the value to the default value
- [basic_json_view::empty](../basic_json_view/empty.md) - the same check on a zero-copy view
## Version history
+5 -10
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@@ -7,12 +7,7 @@ const_iterator end() const noexcept;
Returns an iterator to one past the last element.
<div class="nj-fig-wrap" markdown>
--8<-- "images/range-begin-end.svg"
</div>
<p class="nj-caption" markdown>`end()` points to the position after the last element and `begin()` to the first element;
the dashed cell is the past-the-last position, which must not be dereferenced.</p>
![Illustration from cppreference.com](../../images/range-begin-end.svg)
## Return value
@@ -44,11 +39,11 @@ Constant.
## See also
- [`begin`](begin.md) - returns an iterator to the first element
- [`cend`](cend.md) - returns a const iterator to one past the last element
- [`rend`](rend.md) - returns a reverse iterator to one before the first element
- [begin](begin.md) returns an iterator to the first element
- [cend](cend.md) returns a const iterator to one past the last element
- [rend](rend.md) returns a reverse iterator to one before the first element
- [Iterators](../../features/iterators.md) - the article on iterators
- [`basic_json_view::end`](../basic_json_view/end.md) - the same iteration on a zero-copy view
- [basic_json_view::end](../basic_json_view/end.md) - the same iteration on a zero-copy view
## Version history
+2 -3
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@@ -60,9 +60,8 @@ Constant.
## See also
- [`start_pos`](start_pos.md) - to access the start position
- [`JSON_DIAGNOSTIC_POSITIONS`](../macros/json_diagnostic_positions.md) - overview of the supported conversions
- [Parsing and Exceptions](../../features/parsing/parse_exceptions.md) - handling parse errors and locating them in the input
- [start_pos](start_pos.md) to access the start position
- [JSON_DIAGNOSTIC_POSITIONS](../macros/json_diagnostic_positions.md) for an overview of the diagnostic positions
## Version history
+2 -2
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@@ -204,8 +204,8 @@ Strong exception safety: if an exception occurs, the original value stays intact
## See also
- [`clear`](clear.md) - clears the contents
- [`insert`](insert.md) - add values to an array/object
- [clear](clear.md) clears the contents
- [insert](insert.md) add values to an array/object
- [Modifying values](../../features/modifying_values.md) - the article on modifying values
## Version history
@@ -61,7 +61,7 @@ keep
## See also
- [`dump`](dump.md) - serializes a JSON value, with an `error_handler_t` parameter to configure invalid UTF-8 handling
- [dump](dump.md) serializes a JSON value, with an `error_handler_t` parameter to configure invalid UTF-8 handling
- [Handling invalid UTF-8](../../features/serialization.md#handling-invalid-utf-8) - the article on handling invalid UTF-8
## Version history
+1 -8
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@@ -40,9 +40,6 @@ classDiagram
style json_exception fill:#CCCCFF
```
<p class="nj-caption" markdown>Class hierarchy of the library's exceptions; arrows point from a derived class to its
base class, and the highlighted box is `basic_json::exception`.</p>
Subclasses:
- [`parse_error`](parse_error.md) for exceptions indicating a parse error
@@ -83,11 +80,7 @@ constructor.
## See also
- [List of exceptions](../../home/exceptions.md) - overview of all exceptions thrown by the library
- [Working Without Exceptions](../../features/no_exceptions.md) - using the library without exceptions
- [`JSON_DIAGNOSTICS`](../macros/json_diagnostics.md) - extended exception messages with the path of the failing value
- [Parsing and Exceptions](../../features/parsing/parse_exceptions.md) - parsing alternatives that do not throw
- [Debugging](../../home/debugging.md) - debugging aids
[List of exceptions](../../home/exceptions.md)
## Version history
+3 -4
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@@ -91,11 +91,10 @@ Logarithmic in the size of the JSON object.
## See also
- [`count`](count.md) - returns the number of occurrences of a key
- [`contains`](contains.md) - checks whether a key exists
- [`basic_json_view::find`](../basic_json_view/find.md) - the same lookup on a zero-copy view (a duplicate key resolves
- [count](count.md) returns the number of occurrences of a key
- [contains](contains.md) checks whether a key exists
- [basic_json_view::find](../basic_json_view/find.md) - the same lookup on a zero-copy view (a duplicate key resolves
to the first member, whereas `parse()` keeps the last)
- [Element Access](../../features/element_access/index.md#does-this-key-exist) - how to test whether a key exists
## Version history
+1 -2
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@@ -58,8 +58,7 @@ Empty objects and arrays are flattened to `#!json null` and will not be reconstr
## See also
- [`unflatten`](unflatten.md) - the reverse function
- [JSON Pointer](../../features/json_pointer.md#flatten-unflatten) - the article on JSON Pointer and flattening
- [unflatten](unflatten.md) the reverse function
## Version history
+2 -2
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@@ -86,8 +86,8 @@ std::string format_as(const BasicJsonType& j)
## See also
- [`dump`](dump.md) - serialize a JSON value to a string
- [`std::formatter<basic_json>`](std_formatter.md) - the `std::format` (C++20) equivalent
- [dump](dump.md)
- [std::formatter<basic_json>](std_formatter.md) - the `std::format` (C++20) equivalent
- [Serialization](../../features/serialization.md) - the serialization article
## Version history
+6 -10
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@@ -107,16 +107,12 @@ Linear in the size of the input.
## See also
- [BJData](../../features/binary_formats/bjdata.md) - the format, its byte layout and how values are mapped
- [Binary formats](../../features/binary_formats/index.md) - overview and comparison of the supported binary formats
- [Parsing untrusted input](../../features/parsing/untrusted_input.md) - limits and safe handling of hostile data
- [Binary values](../../features/binary_values.md) - how binary values and subtypes are handled
- [`to_bjdata`](to_bjdata.md) - create a BJData serialization of a JSON value
- [`from_cbor`](from_cbor.md) - create a JSON value from an input in CBOR format
- [`from_msgpack`](from_msgpack.md) - create a JSON value from an input in MessagePack format
- [`from_bson`](from_bson.md) - create a JSON value from an input in BSON format
- [`from_ubjson`](from_ubjson.md) - create a JSON value from an input in UBJSON format
- [`from_bon8`](from_bon8.md) - create a JSON value from an input in BON8 format
- [to_bjdata](to_bjdata.md) create a BJData serialization of a JSON value
- [from_cbor](from_cbor.md) create a JSON value from an input in CBOR format
- [from_msgpack](from_msgpack.md) create a JSON value from an input in MessagePack format
- [from_bson](from_bson.md) create a JSON value from an input in BSON format
- [from_ubjson](from_ubjson.md) create a JSON value from an input in UBJSON format
- [from_bon8](from_bon8.md) create a JSON value from an input in BON8 format
## Version history
+6 -9
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@@ -96,15 +96,12 @@ Linear in the size of the input.
## See also
- [BON8](../../features/binary_formats/bon8.md) - the format, its byte layout and how values are mapped
- [Binary formats](../../features/binary_formats/index.md) - overview and comparison of the supported binary formats
- [Parsing untrusted input](../../features/parsing/untrusted_input.md) - limits and safe handling of hostile data
- [`to_bon8`](to_bon8.md) - create a BON8 serialization of a JSON value
- [`from_cbor`](from_cbor.md) - create a JSON value from an input in CBOR format
- [`from_msgpack`](from_msgpack.md) - create a JSON value from an input in MessagePack format
- [`from_bson`](from_bson.md) - create a JSON value from an input in BSON format
- [`from_ubjson`](from_ubjson.md) - create a JSON value from an input in UBJSON format
- [`from_bjdata`](from_bjdata.md) - create a JSON value from an input in BJData format
- [to_bon8](to_bon8.md) create a BON8 serialization of a JSON value
- [from_cbor](from_cbor.md) create a JSON value from an input in CBOR format
- [from_msgpack](from_msgpack.md) create a JSON value from an input in MessagePack format
- [from_bson](from_bson.md) create a JSON value from an input in BSON format
- [from_ubjson](from_ubjson.md) create a JSON value from an input in UBJSON format
- [from_bjdata](from_bjdata.md) create a JSON value from an input in BJData format
## Version history
+7 -11
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@@ -108,17 +108,13 @@ Linear in the size of the input.
## See also
- [BSON](../../features/binary_formats/bson.md) - the format, its byte layout and how values are mapped
- [Binary formats](../../features/binary_formats/index.md) - overview and comparison of the supported binary formats
- [Parsing untrusted input](../../features/parsing/untrusted_input.md) - limits and safe handling of hostile data
- [Binary values](../../features/binary_values.md) - how binary values and subtypes are handled
- [BSON specification](http://bsonspec.org/spec.html) - specification of the BSON format
- [`to_bson`](to_bson.md) - the analogous serialization
- [`from_cbor`](from_cbor.md) - the related CBOR format
- [`from_msgpack`](from_msgpack.md) - the related MessagePack format
- [`from_ubjson`](from_ubjson.md) - the related UBJSON format
- [`from_bjdata`](from_bjdata.md) - the related BJData format
- [`from_bon8`](from_bon8.md) - the related BON8 format
- [BSON specification](http://bsonspec.org/spec.html)
- [to_bson](to_bson.md) for the analogous serialization
- [from_cbor](from_cbor.md) for the related CBOR format
- [from_msgpack](from_msgpack.md) for the related MessagePack format
- [from_ubjson](from_ubjson.md) for the related UBJSON format
- [from_bjdata](from_bjdata.md) for the related BJData format
- [from_bon8](from_bon8.md) for the related BON8 format
## Version history
+6 -10
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@@ -114,16 +114,12 @@ Linear in the size of the input.
## See also
- [CBOR](../../features/binary_formats/cbor.md) - the format, its byte layout and how values are mapped
- [Binary formats](../../features/binary_formats/index.md) - overview and comparison of the supported binary formats
- [Parsing untrusted input](../../features/parsing/untrusted_input.md) - limits and safe handling of hostile data
- [Binary values](../../features/binary_values.md) - how binary values and subtypes are handled
- [`to_cbor`](to_cbor.md) - create a CBOR serialization of a JSON value
- [`from_msgpack`](from_msgpack.md) - create a JSON value from an input in MessagePack format
- [`from_bson`](from_bson.md) - create a JSON value from an input in BSON format
- [`from_ubjson`](from_ubjson.md) - create a JSON value from an input in UBJSON format
- [`from_bjdata`](from_bjdata.md) - create a JSON value from an input in BJData format
- [`from_bon8`](from_bon8.md) - create a JSON value from an input in BON8 format
- [to_cbor](to_cbor.md) create a CBOR serialization of a JSON value
- [from_msgpack](from_msgpack.md) create a JSON value from an input in MessagePack format
- [from_bson](from_bson.md) create a JSON value from an input in BSON format
- [from_ubjson](from_ubjson.md) create a JSON value from an input in UBJSON format
- [from_bjdata](from_bjdata.md) create a JSON value from an input in BJData format
- [from_bon8](from_bon8.md) create a JSON value from an input in BON8 format
## Version history
@@ -107,16 +107,12 @@ Linear in the size of the input.
## See also
- [MessagePack](../../features/binary_formats/messagepack.md) - the format, its byte layout and how values are mapped
- [Binary formats](../../features/binary_formats/index.md) - overview and comparison of the supported binary formats
- [Parsing untrusted input](../../features/parsing/untrusted_input.md) - limits and safe handling of hostile data
- [Binary values](../../features/binary_values.md) - how binary values and subtypes are handled
- [`to_msgpack`](to_msgpack.md) - create a MessagePack serialization of a JSON value
- [`from_cbor`](from_cbor.md) - create a JSON value from an input in CBOR format
- [`from_bson`](from_bson.md) - create a JSON value from an input in BSON format
- [`from_ubjson`](from_ubjson.md) - create a JSON value from an input in UBJSON format
- [`from_bjdata`](from_bjdata.md) - create a JSON value from an input in BJData format
- [`from_bon8`](from_bon8.md) - create a JSON value from an input in BON8 format
- [to_msgpack](to_msgpack.md) create a MessagePack serialization of a JSON value
- [from_cbor](from_cbor.md) create a JSON value from an input in CBOR format
- [from_bson](from_bson.md) create a JSON value from an input in BSON format
- [from_ubjson](from_ubjson.md) create a JSON value from an input in UBJSON format
- [from_bjdata](from_bjdata.md) create a JSON value from an input in BJData format
- [from_bon8](from_bon8.md) create a JSON value from an input in BON8 format
## Version history
+6 -10
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@@ -107,16 +107,12 @@ Linear in the size of the input.
## See also
- [UBJSON](../../features/binary_formats/ubjson.md) - the format, its byte layout and how values are mapped
- [Binary formats](../../features/binary_formats/index.md) - overview and comparison of the supported binary formats
- [Parsing untrusted input](../../features/parsing/untrusted_input.md) - limits and safe handling of hostile data
- [Binary values](../../features/binary_values.md) - how binary values and subtypes are handled
- [`to_ubjson`](to_ubjson.md) - create a UBJSON serialization of a JSON value
- [`from_cbor`](from_cbor.md) - create a JSON value from an input in CBOR format
- [`from_msgpack`](from_msgpack.md) - create a JSON value from an input in MessagePack format
- [`from_bson`](from_bson.md) - create a JSON value from an input in BSON format
- [`from_bjdata`](from_bjdata.md) - create a JSON value from an input in BJData format
- [`from_bon8`](from_bon8.md) - create a JSON value from an input in BON8 format
- [to_ubjson](to_ubjson.md) create a UBJSON serialization of a JSON value
- [from_cbor](from_cbor.md) create a JSON value from an input in CBOR format
- [from_msgpack](from_msgpack.md) create a JSON value from an input in MessagePack format
- [from_bson](from_bson.md) create a JSON value from an input in BSON format
- [from_bjdata](from_bjdata.md) create a JSON value from an input in BJData format
- [from_bon8](from_bon8.md) create a JSON value from an input in BON8 format
## Version history
+2 -3
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@@ -50,10 +50,9 @@ Constant.
## See also
- [`back`](back.md) - to access the last element
- [`basic_json_view::front`](../basic_json_view/front.md) - the same access on a zero-copy view (document order, not
- [back](back.md) to access the last element
- [basic_json_view::front](../basic_json_view/front.md) - the same access on a zero-copy view (document order, not
sorted; duplicate keys are visited)
- [Element Access](../../features/element_access/index.md) - overview of all ways to access elements
## Version history
+5 -6
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@@ -178,14 +178,13 @@ overload (3).
## See also
- [`get_to`](get_to.md) - convert and write into a passed value
- [`get_ptr`](get_ptr.md) - get a pointer to the stored value
- [`get_ref`](get_ref.md) - get a reference to the stored value
- [`operator ValueType`](operator_ValueType.md) - get a value via implicit conversion
- [get_to](get_to.md) convert and write into a passed value
- [get_ptr](get_ptr.md) get a pointer to the stored value
- [get_ref](get_ref.md) get a reference to the stored value
- [operator ValueType](operator_ValueType.md) get a value via implicit conversion
- [Converting values](../../features/conversions.md) - the type conversions article
- [`basic_json_view::get`](../basic_json_view/get.md) - the same conversion on a zero-copy view (many types are
- [basic_json_view::get](../basic_json_view/get.md) - the same conversion on a zero-copy view (many types are
converted without ever building a `basic_json` value)
- [Arbitrary Type Conversions](../../features/arbitrary_types.md) - make your own types usable with `get`
## Version history
@@ -36,7 +36,7 @@ Constant.
## See also
- [`basic_json`](index.md#template-parameters) - the class template, with `AllocatorType` as one of its template parameters
- [basic_json](index.md#template-parameters) the class template, with `AllocatorType` as one of its template parameters
- [Template Parameter Requirements](../../features/types/template_parameters.md#allocatortype) - the requirements for `AllocatorType`
## Version history
@@ -42,11 +42,8 @@ Constant.
## See also
- [Binary values](../../features/binary_values.md) - how binary values and subtypes are handled
- [`binary`](binary.md) - create a binary value
- [`is_binary`](is_binary.md) - check whether a value is binary
- [`get`](get.md) - get a value (explicit conversion)
- [`get_ref`](get_ref.md) - get a reference to the stored value
- [get](get.md) get a value (explicit conversion)
- [get_ref](get_ref.md) get a reference to the stored value
## Version history
+1 -2
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@@ -86,8 +86,7 @@ Constant.
## See also
- [`get_ref()`](get_ref.md) - get a reference value
- [Converting values](../../features/conversions.md) - getting values out, with or without copying
- [get_ref()](get_ref.md) get a reference value
## Version history
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@@ -60,10 +60,9 @@ Constant.
## See also
- [`get_ptr()`](get_ptr.md) - get a pointer value
- [`basic_json_view::get_string`](../basic_json_view/get_string.md) - the closest counterpart on a zero-copy view: a
- [get_ptr()](get_ptr.md) get a pointer value
- [basic_json_view::get_string](../basic_json_view/get_string.md) - the closest counterpart on a zero-copy view: a
string without a copy, but as a view rather than a reference to a value that must already exist
- [Converting values](../../features/conversions.md) - getting values out, with or without copying
## Version history
+4 -5
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@@ -68,12 +68,11 @@ Depends on the `json_serializer<ValueType>::from_json()` implementation.
## See also
- [`get`](get.md) - get a value (explicit conversion)
- [`get_ref`](get_ref.md) - get a reference to the stored value
- [`get_ptr`](get_ptr.md) - get a pointer to the stored value
- [get](get.md) get a value (explicit conversion)
- [get_ref](get_ref.md) get a reference to the stored value
- [get_ptr](get_ptr.md) get a pointer to the stored value
- [Converting values](../../features/conversions.md) - the type conversions article
- [`basic_json_view::get_to`](../basic_json_view/get_to.md) - the same conversion on a zero-copy view
- [Arbitrary Type Conversions](../../features/arbitrary_types.md) - make your own types usable with `get_to`
- [basic_json_view::get_to](../basic_json_view/get_to.md) - the same conversion on a zero-copy view
## Version history
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@@ -188,7 +188,7 @@ The class satisfies the following concept requirements:
Functions to inspect the type of a JSON value.
- [**type**](type.md) - return the type of the JSON value
- [`operator value_t`](operator_value_t.md) - return the type of the JSON value
- [**operator value_t**](operator_value_t.md) - return the type of the JSON value
- [**type_name**](type_name.md) - return the type as string
- [**is_primitive**](is_primitive.md) - return whether the type is primitive
- [**is_structured**](is_structured.md) - return whether the type is structured
@@ -217,7 +217,7 @@ Direct access to the stored value of a JSON value.
- [**get_to**](get_to.md) - get a value and write it to a destination
- [**get_ptr**](get_ptr.md) - get a pointer value
- [**get_ref**](get_ref.md) - get a reference value
- [`operator ValueType`](operator_ValueType.md) - get a value
- [**operator ValueType**](operator_ValueType.md) - get a value
- [**get_binary**](get_binary.md) - get a binary value
- [**as_base_class**](as_base_class.md) - access the custom base class
@@ -358,15 +358,10 @@ Access to the JSON value
## See also
- [RFC 8259: The JavaScript Object Notation (JSON) Data Interchange Format](https://tools.ietf.org/html/rfc8259) -
specification of the JSON data interchange format
- [`basic_json_document`](../basic_json_document/index.md) - / [`basic_json_view`](../basic_json_view/index.md) - parse a JSON
- [RFC 8259: The JavaScript Object Notation (JSON) Data Interchange Format](https://tools.ietf.org/html/rfc8259)
- [basic_json_document](../basic_json_document/index.md) / [basic_json_view](../basic_json_view/index.md) - parse a JSON
text into a flat index and read it through a view
- [Zero-copy JSON views](../../features/json_view.md) - when to use a document and a view instead of a `basic_json`
- [Types](../../features/types/index.md) - how JSON values are stored and which types exist
- [Converting values](../../features/conversions.md) - get values out of a JSON value and put values in
- [Creating JSON values](../../features/creating_values.md) - all the ways to build a JSON value
- [Arbitrary Type Conversions](../../features/arbitrary_types.md) - convert your own types to and from JSON
## Version history
@@ -53,9 +53,8 @@ bon8
## See also
- [`sax_parse`](sax_parse.md) - generic SAX parse interface, taking an `input_format_t` to select the input format
- [`cbor_tag_handler_t`](cbor_tag_handler_t.md) - configures how CBOR tags are treated while parsing
- [Binary Formats](../../features/binary_formats/index.md) - CBOR, MessagePack, BSON, and other formats
- [sax_parse](sax_parse.md) generic SAX parse interface, taking an `input_format_t` to select the input format
- [cbor_tag_handler_t](cbor_tag_handler_t.md) configures how CBOR tags are treated while parsing
## Version history
+4 -5
View File
@@ -185,11 +185,10 @@ Strong exception safety: if an exception occurs, the original value stays intact
## See also
- [`emplace`](emplace.md) - add a value to an object
- [`emplace_back`](emplace_back.md) - add a value to an array
- [`push_back`](push_back.md) - add a value to an array/object
- [`update`](update.md) - merges objects
- [Modifying values](../../features/modifying_values.md) - the article on modifying values
- [emplace](emplace.md) add a value to an object
- [emplace_back](emplace_back.md) add a value to an array
- [push_back](push_back.md) add a value to an array/object
- [update](update.md) merges objects
## Version history
@@ -40,9 +40,6 @@ classDiagram
style json_invalid_iterator fill:#CCCCFF
```
<p class="nj-caption" markdown>Class hierarchy of the library's exceptions; arrows point from a derived class to its
base class, and the highlighted box is `basic_json::invalid_iterator`.</p>
## Member functions
- **what** - returns explanatory string
@@ -69,14 +66,12 @@ base class, and the highlighted box is `basic_json::invalid_iterator`.</p>
## See also
- [`exception`](exception.md) - the base class of all exceptions thrown by the library
- [List of iterator errors](../../home/exceptions.md#iterator-errors) - overview of iterator errors (`invalid_iterator`)
- [`parse_error`](parse_error.md) - exceptions indicating a parse error
- [`type_error`](type_error.md) - exceptions indicating executing a member function with a wrong type
- [`out_of_range`](out_of_range.md) - exceptions indicating access out of the defined range
- [`other_error`](other_error.md) - exceptions indicating other library errors
- [Exceptions](../../home/exceptions.md) - all exceptions and their error codes
- [`JSON_DIAGNOSTICS`](../macros/json_diagnostics.md) - extended exception messages with the path of the failing value
- [`exception`](exception.md) for the base class of all exceptions thrown by the library
- [List of iterator errors](../../home/exceptions.md#iterator-errors)
- [`parse_error`](parse_error.md) for exceptions indicating a parse error
- [`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
## Version history
+5 -6
View File
@@ -36,12 +36,11 @@ Constant.
## See also
- [`is_object`](is_object.md) - checks whether the JSON value is an object
- [`is_structured`](is_structured.md) - checks whether the JSON value is structured (array or object)
- [`type`](type.md) - returns the type of the JSON value
- [`array_t`](array_t.md) - the type used to store JSON arrays
- [`basic_json_view::is_array`](../basic_json_view/is_array.md) - the same check on a zero-copy view
- [Types](../../features/types/index.md) - the JSON value types and how they are stored
- [is_object](is_object.md) checks whether the JSON value is an object
- [is_structured](is_structured.md) checks whether the JSON value is structured (array or object)
- [type](type.md) returns the type of the JSON value
- [array_t](array_t.md) the type used to store JSON arrays
- [basic_json_view::is_array](../basic_json_view/is_array.md) - the same check on a zero-copy view
## Version history
+4 -5
View File
@@ -36,11 +36,10 @@ Constant.
## See also
- [Binary values](../../features/binary_values.md) - how binary values and subtypes are handled
- [`is_primitive`](is_primitive.md) - checks whether the JSON value is primitive
- [`binary_t`](binary_t.md) - the type used to store binary values
- [`get_binary`](get_binary.md) - returns a reference to the stored binary value
- [`basic_json_view::is_binary`](../basic_json_view/is_binary.md) - the same check on a zero-copy view
- [is_primitive](is_primitive.md) checks whether the JSON value is primitive
- [binary_t](binary_t.md) the type used to store binary values
- [get_binary](get_binary.md) returns a reference to the stored binary value
- [basic_json_view::is_binary](../basic_json_view/is_binary.md) - the same check on a zero-copy view
## Version history
@@ -36,10 +36,9 @@ Constant.
## See also
- [`boolean_t`](boolean_t.md) - the type used to store JSON booleans
- [`is_primitive`](is_primitive.md) - checks whether the JSON value is primitive
- [`basic_json_view::is_boolean`](../basic_json_view/is_boolean.md) - the same check on a zero-copy view
- [Types](../../features/types/index.md) - the JSON value types and how they are stored
- [boolean_t](boolean_t.md) the type used to store JSON booleans
- [is_primitive](is_primitive.md) checks whether the JSON value is primitive
- [basic_json_view::is_boolean](../basic_json_view/is_boolean.md) - the same check on a zero-copy view
## Version history
@@ -87,9 +87,8 @@ with `allow_exceptions` set to `#!cpp false`: a parse error then yields a discar
## See also
- [`basic_json_view::is_discarded`](../basic_json_view/is_discarded.md) - the corresponding check on a zero-copy view,
- [basic_json_view::is_discarded](../basic_json_view/is_discarded.md) - the corresponding check on a zero-copy view,
which is `#!cpp true` if the view refers to no value
- [Types](../../features/types/index.md) - the JSON value types and how they are stored
## Version history
+5 -6
View File
@@ -36,12 +36,11 @@ Constant.
## See also
- [`is_array`](is_array.md) - checks whether the JSON value is an array
- [`is_object`](is_object.md) - checks whether the JSON value is an object
- [`type`](type.md) - returns the type of the JSON value
- [`value_t`](value_t.md) - the enumeration of JSON types
- [`basic_json_view::is_null`](../basic_json_view/is_null.md) - the same check on a zero-copy view
- [Types](../../features/types/index.md) - the JSON value types and how they are stored
- [is_array](is_array.md) checks whether the JSON value is an array
- [is_object](is_object.md) checks whether the JSON value is an object
- [type](type.md) returns the type of the JSON value
- [value_t](value_t.md) the enumeration of JSON types
- [basic_json_view::is_null](../basic_json_view/is_null.md) - the same check on a zero-copy view
## Version history
+4 -6
View File
@@ -46,12 +46,10 @@ constexpr bool is_number() const noexcept
## See also
- [`is_number_integer()`](is_number_integer.md) - check if the value is an integer or unsigned integer number
- [`is_number_unsigned()`](is_number_unsigned.md) - check if the value is an unsigned integer number
- [`is_number_float()`](is_number_float.md) - check if the value is a floating-point number
- [`basic_json_view::is_number`](../basic_json_view/is_number.md) - the same check on a zero-copy view
- [Types](../../features/types/index.md) - the JSON value types and how they are stored
- [Number Handling](../../features/types/number_handling.md) - how numbers are stored and converted
- [is_number_integer()](is_number_integer.md) check if the value is an integer or unsigned integer number
- [is_number_unsigned()](is_number_unsigned.md) check if the value is an unsigned integer number
- [is_number_float()](is_number_float.md) check if the value is a floating-point number
- [basic_json_view::is_number](../basic_json_view/is_number.md) - the same check on a zero-copy view
## Version history
@@ -37,12 +37,10 @@ Constant.
## See also
- [`is_number()`](is_number.md) - check if the value is a number
- [`is_number_integer()`](is_number_integer.md) - check if the value is an integer or unsigned integer number
- [`is_number_unsigned()`](is_number_unsigned.md) - check if the value is an unsigned integer number
- [`basic_json_view::is_number_float`](../basic_json_view/is_number_float.md) - the same check on a zero-copy view
- [Types](../../features/types/index.md) - the JSON value types and how they are stored
- [Number Handling](../../features/types/number_handling.md) - how numbers are stored and converted
- [is_number()](is_number.md) check if the value is a number
- [is_number_integer()](is_number_integer.md) check if the value is an integer or unsigned integer number
- [is_number_unsigned()](is_number_unsigned.md) check if the value is an unsigned integer number
- [basic_json_view::is_number_float](../basic_json_view/is_number_float.md) - the same check on a zero-copy view
## Version history
@@ -37,12 +37,10 @@ Constant.
## See also
- [`is_number()`](is_number.md) - check if the value is a number
- [`is_number_unsigned()`](is_number_unsigned.md) - check if the value is an unsigned integer number
- [`is_number_float()`](is_number_float.md) - check if the value is a floating-point number
- [`basic_json_view::is_number_integer`](../basic_json_view/is_number_integer.md) - the same check on a zero-copy view
- [Types](../../features/types/index.md) - the JSON value types and how they are stored
- [Number Handling](../../features/types/number_handling.md) - how numbers are stored and converted
- [is_number()](is_number.md) check if the value is a number
- [is_number_unsigned()](is_number_unsigned.md) check if the value is an unsigned integer number
- [is_number_float()](is_number_float.md) check if the value is a floating-point number
- [basic_json_view::is_number_integer](../basic_json_view/is_number_integer.md) - the same check on a zero-copy view
## Version history
@@ -40,12 +40,10 @@ Constant.
## See also
- [`is_number()`](is_number.md) - check if the value is a number
- [`is_number_integer()`](is_number_integer.md) - check if the value is an integer or unsigned integer number
- [`is_number_float()`](is_number_float.md) - check if the value is a floating-point number
- [`basic_json_view::is_number_unsigned`](../basic_json_view/is_number_unsigned.md) - the same check on a zero-copy view
- [Types](../../features/types/index.md) - the JSON value types and how they are stored
- [Number Handling](../../features/types/number_handling.md) - how numbers are stored and converted
- [is_number()](is_number.md) check if the value is a number
- [is_number_integer()](is_number_integer.md) check if the value is an integer or unsigned integer number
- [is_number_float()](is_number_float.md) check if the value is a floating-point number
- [basic_json_view::is_number_unsigned](../basic_json_view/is_number_unsigned.md) - the same check on a zero-copy view
## Version history
+5 -6
View File
@@ -36,12 +36,11 @@ Constant.
## See also
- [`is_array`](is_array.md) - checks whether the JSON value is an array
- [`is_structured`](is_structured.md) - checks whether the JSON value is structured (array or object)
- [`type`](type.md) - returns the type of the JSON value
- [`object_t`](object_t.md) - the type used to store JSON objects
- [`basic_json_view::is_object`](../basic_json_view/is_object.md) - the same check on a zero-copy view
- [Types](../../features/types/index.md) - the JSON value types and how they are stored
- [is_array](is_array.md) checks whether the JSON value is an array
- [is_structured](is_structured.md) checks whether the JSON value is structured (array or object)
- [type](type.md) returns the type of the JSON value
- [object_t](object_t.md) the type used to store JSON objects
- [basic_json_view::is_object](../basic_json_view/is_object.md) - the same check on a zero-copy view
## Version history
@@ -56,14 +56,13 @@ This library extends primitive types to binary types, because binary types are r
## See also
- [`is_structured()`](is_structured.md) - returns whether the JSON value is structured
- [`is_null()`](is_null.md) - returns whether the JSON value is `null`
- [`is_string()`](is_string.md) - returns whether the JSON value is a string
- [`is_boolean()`](is_boolean.md) - returns whether the JSON value is a boolean
- [`is_number()`](is_number.md) - returns whether the JSON value is a number
- [`is_binary()`](is_binary.md) - returns whether the JSON value is a binary array
- [`basic_json_view::is_primitive`](../basic_json_view/is_primitive.md) - the same check on a zero-copy view
- [Types](../../features/types/index.md) - the JSON value types and how they are stored
- [is_structured()](is_structured.md) returns whether the JSON value is structured
- [is_null()](is_null.md) returns whether the JSON value is `null`
- [is_string()](is_string.md) returns whether the JSON value is a string
- [is_boolean()](is_boolean.md) returns whether the JSON value is a boolean
- [is_number()](is_number.md) returns whether the JSON value is a number
- [is_binary()](is_binary.md) returns whether the JSON value is a binary array
- [basic_json_view::is_primitive](../basic_json_view/is_primitive.md) - the same check on a zero-copy view
## Version history
+4 -5
View File
@@ -36,11 +36,10 @@ Constant.
## See also
- [`is_primitive`](is_primitive.md) - checks whether the JSON value is primitive
- [`type`](type.md) - returns the type of the JSON value
- [`string_t`](string_t.md) - the type used to store JSON strings
- [`basic_json_view::is_string`](../basic_json_view/is_string.md) - the same check on a zero-copy view
- [Types](../../features/types/index.md) - the JSON value types and how they are stored
- [is_primitive](is_primitive.md) checks whether the JSON value is primitive
- [type](type.md) returns the type of the JSON value
- [string_t](string_t.md) the type used to store JSON strings
- [basic_json_view::is_string](../basic_json_view/is_string.md) - the same check on a zero-copy view
## Version history
@@ -54,11 +54,10 @@ Note that though strings are containers in C++, they are treated as primitive va
## See also
- [`is_primitive()`](is_primitive.md) - returns whether JSON value is primitive
- [`is_array()`](is_array.md) - returns whether the value is an array
- [`is_object()`](is_object.md) - returns whether the value is an object
- [`basic_json_view::is_structured`](../basic_json_view/is_structured.md) - the same check on a zero-copy view
- [Types](../../features/types/index.md) - the JSON value types and how they are stored
- [is_primitive()](is_primitive.md) returns whether JSON value is primitive
- [is_array()](is_array.md) returns whether the value is an array
- [is_object()](is_object.md) returns whether the value is an object
- [basic_json_view::is_structured](../basic_json_view/is_structured.md) - the same check on a zero-copy view
## Version history
+4 -5
View File
@@ -54,7 +54,7 @@ using element_type = decltype(*j_object.items().begin());
```
The per-element type (`iteration_proxy_value`) lives in the library's internal `detail` namespace and is
intentionally unspecified as a stable, named type — `decltype` is the supported way to obtain it, but its exact
intentionally unspecified as a stable, named type -- `decltype` is the supported way to obtain it, but its exact
name/definition may change between versions.
## Return value
@@ -97,11 +97,10 @@ When iterating over an array, `key()` will return the index of the element as st
## See also
- [`begin`](begin.md) - returns an iterator to the first element
- [`end`](end.md) - returns an iterator to one past the last element
- [`basic_json_view::items`](../basic_json_view/items.md) - the same range on a zero-copy view (`#!cpp const auto`,
- [begin](begin.md) returns an iterator to the first element
- [end](end.md) returns an iterator to one past the last element
- [basic_json_view::items](../basic_json_view/items.md) - the same range on a zero-copy view (`#!cpp const auto`,
not `#!cpp const auto&`: items are produced on the fly; document order, not sorted; duplicate keys are visited)
- [Iterators](../../features/iterators.md#access-object-keys-during-iteration) - the article on iterating over keys and values
## Version history
@@ -57,7 +57,7 @@ same name. Hidden members remain accessible via [`as_base_class`](as_base_class.
## See also
- [`as_base_class`](as_base_class.md) - access the custom base class
- [as_base_class](as_base_class.md) - access the custom base class
- [Template Parameter Requirements](../../features/types/template_parameters.md#custombaseclass) - the requirements for `CustomBaseClass`
## Version history
@@ -44,11 +44,10 @@ deserializes. See [Template Parameter Requirements](../../features/types/templat
## See also
- [`adl_serializer`](../adl_serializer/index.md) - the default `json_serializer`
- [`get`](get.md) - explicit type conversion using the `json_serializer`'s `from_json()` method
- [`get_to`](get_to.md) - explicit type conversion into a variable using the `json_serializer`'s `from_json()` method
- [adl_serializer](../adl_serializer/index.md) the default `json_serializer`
- [get](get.md) explicit type conversion using the `json_serializer`'s `from_json()` method
- [get_to](get_to.md) explicit type conversion into a variable using the `json_serializer`'s `from_json()` method
- [Arbitrary Type Conversions](../../features/arbitrary_types.md) - the article on converting between JSON values and arbitrary types
- [Template Parameter Requirements](../../features/types/template_parameters.md) - requirements on the `JSONSerializer` template parameter
## Version history
+4 -4
View File
@@ -33,7 +33,7 @@ constant complexity.
## Notes
This function does not return the maximal length of a string stored as JSON value — it returns the maximal number of
This function does not return the maximal length of a string stored as JSON value -- it returns the maximal number of
string elements the JSON value can store which is `1`.
## Examples
@@ -56,9 +56,9 @@ string elements the JSON value can store which is `1`.
## See also
- [`size`](size.md) - returns the number of elements
- [`array_t`](array_t.md) - the type used to store JSON arrays
- [`object_t`](object_t.md) - the type used to store JSON objects
- [size](size.md) returns the number of elements
- [array_t](array_t.md) the type used to store JSON arrays
- [object_t](object_t.md) the type used to store JSON objects
## Version history
@@ -70,10 +70,9 @@ object operation (looking up a key, or adding one to the patch): logarithmic for
## See also
- [RFC 7396 (JSON Merge Patch)](https://tools.ietf.org/html/rfc7396) - specification of JSON Merge Patch
- [`merge_patch`](merge_patch.md) - applies a JSON Merge Patch
- [`diff`](diff.md) - creates a diff as a JSON Patch
- [JSON Merge Patch](../../features/merge_patch.md) - the article on JSON Merge Patch
- [RFC 7396 (JSON Merge Patch)](https://tools.ietf.org/html/rfc7396)
- [merge_patch](merge_patch.md) applies a JSON Merge Patch
- [diff](diff.md) creates a diff as a JSON Patch
## Version history
@@ -85,10 +85,9 @@ cost also includes one copy of `apply_patch` (see the notes below).
## See also
- [RFC 7396 (JSON Merge Patch)](https://tools.ietf.org/html/rfc7396) - specification of JSON Merge Patch
- [`patch`](patch.md) - apply a JSON patch
- [`merge_diff`](merge_diff.md) - creates a diff as a JSON Merge Patch
- [JSON Merge Patch](../../features/merge_patch.md) - the article on JSON Merge Patch
- [RFC 7396 (JSON Merge Patch)](https://tools.ietf.org/html/rfc7396)
- [patch](patch.md) apply a JSON patch
- [merge_diff](merge_diff.md) creates a diff as a JSON Merge Patch
## Version history
+2 -5
View File
@@ -48,11 +48,8 @@ Constant.
## See also
- [`NLOHMANN_JSON_VERSION_MAJOR`](../macros/nlohmann_json_version_major.md) /
[`NLOHMANN_JSON_VERSION_MINOR`](../macros/nlohmann_json_version_major.md) /
[`NLOHMANN_JSON_VERSION_PATCH`](../macros/nlohmann_json_version_major.md) - library version information
- [Integration](../../integration/index.md) - integrate the library
- [Supported Macros](../../features/macros.md) - guide to all supported macros
- [**NLOHMANN_JSON_VERSION_MAJOR**/**NLOHMANN_JSON_VERSION_MINOR**/**NLOHMANN_JSON_VERSION_PATCH**](../macros/nlohmann_json_version_major.md)
\- library version information
## Version history
@@ -84,11 +84,10 @@ Floating-point number values are stored directly inside a `basic_json` type.
## See also
- [`number_integer_t`](number_integer_t.md) - the type used to store JSON integer numbers
- [`number_unsigned_t`](number_unsigned_t.md) - the type used to store JSON unsigned integer numbers
- [`is_number_float`](is_number_float.md) - checks whether the JSON value is a floating-point number
- [number_integer_t](number_integer_t.md) the type used to store JSON integer numbers
- [number_unsigned_t](number_unsigned_t.md) the type used to store JSON unsigned integer numbers
- [is_number_float](is_number_float.md) checks whether the JSON value is a floating-point number
- [Number Handling](../../features/types/number_handling.md) - the article on number handling
- [Template Parameter Requirements](../../features/types/template_parameters.md) - requirements on the number template parameters
## Version history
@@ -80,11 +80,10 @@ Integer number values are stored directly inside a `basic_json` type.
## See also
- [`number_unsigned_t`](number_unsigned_t.md) - the type used to store JSON unsigned integer numbers
- [`number_float_t`](number_float_t.md) - the type used to store JSON floating-point numbers
- [`is_number_integer`](is_number_integer.md) - checks whether the JSON value is a signed integer number
- [number_unsigned_t](number_unsigned_t.md) the type used to store JSON unsigned integer numbers
- [number_float_t](number_float_t.md) the type used to store JSON floating-point numbers
- [is_number_integer](is_number_integer.md) checks whether the JSON value is a signed integer number
- [Number Handling](../../features/types/number_handling.md) - the article on number handling
- [Template Parameter Requirements](../../features/types/template_parameters.md) - requirements on the number template parameters
## Version history
@@ -82,11 +82,10 @@ Integer number values are stored directly inside a `basic_json` type.
## See also
- [`number_integer_t`](number_integer_t.md) - the type used to store JSON integer numbers
- [`number_float_t`](number_float_t.md) - the type used to store JSON floating-point numbers
- [`is_number_unsigned`](is_number_unsigned.md) - checks whether the JSON value is an unsigned integer number
- [number_integer_t](number_integer_t.md) the type used to store JSON integer numbers
- [number_float_t](number_float_t.md) the type used to store JSON floating-point numbers
- [is_number_unsigned](is_number_unsigned.md) checks whether the JSON value is an unsigned integer number
- [Number Handling](../../features/types/number_handling.md) - the article on number handling
- [Template Parameter Requirements](../../features/types/template_parameters.md) - requirements on the number template parameters
## Version history
@@ -27,10 +27,8 @@ and [`default_object_comparator_t`](default_object_comparator_t.md) otherwise.
## See also
- [`object_t`](object_t.md) - the type used to store JSON objects
- [`default_object_comparator_t`](default_object_comparator_t.md) - the fallback comparator used when `object_t` has no `key_compare` member type
- [Template Parameter Requirements](../../features/types/template_parameters.md) - requirements on the `ObjectType` template parameter
- [Object order](../../features/object_order.md) - preserve the insertion order of keys
- [object_t](object_t.md) the type used to store JSON objects
- [default_object_comparator_t](default_object_comparator_t.md) the fallback comparator used when `object_t` has no `key_compare` member type
## Version history
+4 -6
View File
@@ -20,7 +20,7 @@ To store objects in C++, a type is defined by the template parameters described
`ObjectType`
: the container to store objects. Its template parameters must have the same order and meaning as those of
`std::map`; in particular, the third parameter is a comparator. `#!cpp std::unordered_map`, whose third parameter
is a hash function, therefore needs an adapter — see
is a hash function, therefore needs an adapter -- see
[Template Parameter Requirements](../../features/types/template_parameters.md#objecttype) for the full list of
requirements, an adapter example, and the containers that are known to work.
@@ -125,12 +125,10 @@ the object is silently converted as an array of key-value pairs, which is incorr
## See also
- [`array_t`](array_t.md) - the type used to store JSON arrays
- [`string_t`](string_t.md) - the type used to store JSON strings
- [`object_comparator_t`](object_comparator_t.md) - the comparator used to order object keys
- [array_t](array_t.md) the type used to store JSON arrays
- [string_t](string_t.md) the type used to store JSON strings
- [object_comparator_t](object_comparator_t.md) the comparator used to order object keys
- [Object Order](../../features/object_order.md) - the article on object key ordering
- [Types](../../features/types/index.md) - how objects are stored
- [Template Parameter Requirements](../../features/types/template_parameters.md) - requirements on the `ObjectType` template parameter
## Version history
@@ -123,9 +123,8 @@ interpreted as `object_t::value_type` or `std::initializer_list<basic_json>`, se
## See also
- [`emplace_back`](emplace_back.md) - add a value to an array
- [`push_back`](push_back.md) - add a value to an array/object
- [Modifying values](../../features/modifying_values.md) - the article on modifying values
- [emplace_back](emplace_back.md) add a value to an array
- [push_back](push_back.md) add a value to an array/object
## Version history
+2 -3
View File
@@ -45,9 +45,8 @@ Linear.
## See also
- [`basic_json`](basic_json.md) - create a JSON value
- [`swap`](swap.md) - exchanges the contents of two JSON values
- [Creating JSON values](../../features/creating_values.md) - ways to create and assign JSON values
- [basic_json](basic_json.md) create a JSON value
- [swap](swap.md) exchanges the contents of two JSON values
## Version history
+25 -9
View File
@@ -92,12 +92,20 @@ Strong exception safety: if an exception occurs, the original value stays intact
For the **const** version, an object key or array index in `ptr` that does not exist is not reported by an
exception, but is undefined behavior (see the notes below). Use [`at`](at.md) for checked access.
If the **non-const** version throws, the value is left unchanged: values it created for earlier reference tokens
of `ptr` are removed again. This also holds for exceptions such as `#!cpp std::bad_alloc` or
`#!cpp std::length_error` thrown while padding an array up to a very large index. With custom
[template parameters](../../features/types/template_parameters.md), this requires that `erase()` of the object and
array types and the move operations of the custom base class do not throw.
## Complexity
1. Constant if `idx` is in the range of the array. Otherwise, linear in `idx - size()`.
2. Logarithmic in the size of the container.
3. Logarithmic in the size of the container.
4. Logarithmic in the size of the container.
4. Linear in the number of reference tokens of `ptr`; for each of them, logarithmic in the size of the object, or
constant for an array. When the non-const version pads an array with `#!json null` values, it is additionally
linear in `idx - size()` for that array.
## Notes
@@ -145,6 +153,14 @@ Strong exception safety: if an exception occurs, the original value stays intact
specified by the JSON Pointer RFC; it is this library's own, intentional disambiguation rule. See also
[JSON Pointer](../../features/json_pointer.md).
!!! warning "Large array indices"
As the array is filled up with `#!json null` values to the given index, the memory used grows with the index
and not with the size of the pointer: on a 64-bit platform, the index `10000000` allocates about 160 MB.
The library does not limit the index, so check the array indices of a JSON pointer from untrusted input
before using it with the non-const version. See
[Parsing untrusted input](../../features/parsing/untrusted_input.md#json-pointers-and-flattened-keys).
!!! warning "Deprecation"
Overload (4) also accepts a [`json_pointer`](../json_pointer/index.md) whose template argument is a `basic_json`
@@ -274,15 +290,13 @@ Strong exception safety: if an exception occurs, the original value stays intact
## See also
- [Unchecked access](../../features/element_access/unchecked_access.md) - element access without range checking
- [Runtime assertions](../../features/assertions.md) - assertions guarding against undefined behavior
- [`at`](at.md) - access by reference with range checking
- [`value`](value.md) - access with default value
- [`basic_json_view::operator[]`](../basic_json_view/operator%5B%5D.md) - the same access on a zero-copy view (a duplicate
- documentation on [unchecked access](../../features/element_access/unchecked_access.md)
- documentation on [runtime assertions](../../features/assertions.md)
- see [`at`](at.md) for access by reference with range checking
- see [`value`](value.md) for access with default value
- [basic_json_view::operator[]](../basic_json_view/operator%5B%5D.md) - the same access on a zero-copy view (a duplicate
key resolves to the first member, whereas `parse()` keeps the last; a missing key gives a discarded view instead of
undefined behavior)
- [Element Access](../../features/element_access/index.md) - overview of all ways to access elements
- [JSON Pointer](../../features/json_pointer.md) - access nested values with a pointer
## Version history
@@ -296,4 +310,6 @@ Strong exception safety: if an exception occurs, the original value stays intact
4. Added in version 2.0.0. A missing array index in the const version is guarded by a runtime assertion since
version 3.13.0. Throws [`parse_error.109`](../../home/exceptions.md#jsonexceptionparse_error109) instead of
[`out_of_range.404`](../../home/exceptions.md#jsonexceptionout_of_range404) for a one-character array index that is not
a digit (e.g., `/x`) in version 3.13.0, as it already did for longer ones.
a digit (e.g., `/x`) in version 3.13.0, as it already did for longer ones. Fixed in version 3.13.0 to leave the value
unchanged if the non-const version throws (strong exception safety, as documented); before, values created for earlier
reference tokens of `ptr` were kept.
@@ -84,7 +84,7 @@ Linear in the size of the JSON value.
## See also
- [`get`](get.md) - get a value (explicit conversion)
- [get](get.md) get a value (explicit conversion)
- [Converting values](../../features/conversions.md) - the type conversions article
## Version history
@@ -168,9 +168,9 @@ Linear.
## See also
- [`operator!=`](operator_ne.md) - compare for inequality
- [`operator<=>`](operator_spaceship.md) - comparison: 3-way (C++20)
- [`basic_json_view::operator==`](../basic_json_view/operator_eq.md) - the same comparison on a zero-copy view, without
- [operator!=](operator_ne.md) compare for inequality
- [operator<=>](operator_spaceship.md) comparison: 3-way (C++20)
- [basic_json_view::operator==](../basic_json_view/operator_eq.md) - the same comparison on a zero-copy view, without
building a `basic_json` value for it
## Version history
@@ -93,7 +93,7 @@ Linear.
## See also
- [`operator<=>`](operator_spaceship.md) - comparison: 3-way
- [**operator<=>**](operator_spaceship.md) comparison: 3-way
## Version history
@@ -83,7 +83,7 @@ Linear.
## See also
- [`operator<=>`](operator_spaceship.md) - comparison: 3-way
- [**operator<=>**](operator_spaceship.md) comparison: 3-way
## Version history
@@ -94,7 +94,7 @@ Linear.
## See also
- [`operator<=>`](operator_spaceship.md) - comparison: 3-way
- [**operator<=>**](operator_spaceship.md) comparison: 3-way
## Version history
@@ -94,7 +94,7 @@ Linear.
## See also
- [`operator<=>`](operator_spaceship.md) - comparison: 3-way
- [**operator<=>**](operator_spaceship.md) comparison: 3-way
## Version history
@@ -93,9 +93,9 @@ Linear.
## See also
- [`operator==`](operator_eq.md) - comparison: equal
- [`operator<=>`](operator_spaceship.md) - comparison: 3-way (C++20)
- [`basic_json_view::operator!=`](../basic_json_view/operator_ne.md) - the same comparison on a zero-copy view, without
- [operator==](operator_eq.md) comparison: equal
- [operator<=>](operator_spaceship.md) comparison: 3-way (C++20)
- [basic_json_view::operator!=](../basic_json_view/operator_ne.md) - the same comparison on a zero-copy view, without
building a `basic_json` value for it
## Version history
@@ -88,12 +88,12 @@ Linear.
## See also
- [`operator==`](operator_eq.md) - comparison: equal
- [`operator!=`](operator_ne.md) - comparison: not equal
- [`operator<`](operator_lt.md) - comparison: less than
- [`operator<=`](operator_le.md) - comparison: less than or equal
- [`operator>`](operator_gt.md) - comparison: greater than
- [`operator>=`](operator_ge.md) - comparison: greater than or equal
- [**operator==**](operator_eq.md) - comparison: equal
- [**operator!=**](operator_ne.md) - comparison: not equal
- [**operator<**](operator_lt.md) - comparison: less than
- [**operator<=**](operator_le.md) - comparison: less than or equal
- [**operator>**](operator_gt.md) - comparison: greater than
- [**operator>=**](operator_ge.md) - comparison: greater than or equal
## Version history
@@ -49,9 +49,8 @@ Constant.
## See also
- [`type`](type.md) - named member function equivalent to this implicit conversion operator
- [`value_t`](value_t.md) - the enumeration of JSON types
- [Types](../../features/types/index.md) - the JSON value types
- [type](type.md) named member function equivalent to this implicit conversion operator
- [value_t](value_t.md) the enumeration of JSON types
## Version history
+6 -11
View File
@@ -40,9 +40,6 @@ classDiagram
style json_other_error fill:#CCCCFF
```
<p class="nj-caption" markdown>Class hierarchy of the library's exceptions; arrows point from a derived class to its
base class, and the highlighted box is `basic_json::other_error`.</p>
## Member functions
- **what** - returns explanatory string
@@ -69,14 +66,12 @@ base class, and the highlighted box is `basic_json::other_error`.</p>
## See also
- [`exception`](exception.md) - the base class of all exceptions thrown by the library
- [List of other errors](../../home/exceptions.md#further-exceptions) - overview of further errors (`other_error`)
- [`parse_error`](parse_error.md) - exceptions indicating a parse error
- [`invalid_iterator`](invalid_iterator.md) - exceptions indicating errors with iterators
- [`type_error`](type_error.md) - exceptions indicating executing a member function with a wrong type
- [`out_of_range`](out_of_range.md) - exceptions indicating access out of the defined range
- [Exceptions](../../home/exceptions.md) - all exceptions and their error codes
- [`JSON_DIAGNOSTICS`](../macros/json_diagnostics.md) - extended exception messages with the path of the failing value
- [`exception`](exception.md) for the base class of all exceptions thrown by the library
- [List of other errors](../../home/exceptions.md#further-exceptions)
- [`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
## Version history
@@ -41,9 +41,6 @@ classDiagram
style json_out_of_range fill:#CCCCFF
```
<p class="nj-caption" markdown>Class hierarchy of the library's exceptions; arrows point from a derived class to its
base class, and the highlighted box is `basic_json::out_of_range`.</p>
## Member functions
- **what** - returns explanatory string
@@ -70,15 +67,12 @@ base class, and the highlighted box is `basic_json::out_of_range`.</p>
## See also
- [`exception`](exception.md) - the base class of all exceptions thrown by the library
- [List of out-of-range errors](../../home/exceptions.md#out-of-range) - overview of out-of-range errors
(`out_of_range`)
- [`parse_error`](parse_error.md) - exceptions indicating a parse error
- [`invalid_iterator`](invalid_iterator.md) - exceptions indicating errors with iterators
- [`type_error`](type_error.md) - exceptions indicating executing a member function with a wrong type
- [`other_error`](other_error.md) - exceptions indicating other library errors
- [Exceptions](../../home/exceptions.md) - all exceptions and their error codes
- [`JSON_DIAGNOSTICS`](../macros/json_diagnostics.md) - extended exception messages with the path of the failing value
- [`exception`](exception.md) for the base class of all exceptions thrown by the library
- [List of out-of-range errors](../../home/exceptions.md#out-of-range)
- [`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
- [`other_error`](other_error.md) for exceptions indicating other library errors
## Version history
+3 -9
View File
@@ -282,21 +282,15 @@ outside of a string, invalid) byte; see the [FAQ entry](../../home/faq.md#nul-by
## See also
- [`accept`](accept.md) - check if the input is valid JSON
- [`sax_parse`](sax_parse.md) - parse input using the SAX interface
- [`operator>>`](../operator_gtgt.md) - deserialize from stream
- [accept](accept.md) - check if the input is valid JSON
- [sax_parse](sax_parse.md) - parse input using the SAX interface
- [operator>>](../operator_gtgt.md) - deserialize from stream
- [`JSON_STRICT_NUL_HANDLING`](../macros/json_strict_nul_handling.md) - opt in to rejecting a NUL byte in the input
instead of treating it as end of input
- [`JSON_DISABLE_STREAM_BULK_SCAN`](../macros/json_disable_stream_bulk_scan.md) - read a `std::istream` one character
at a time
- [`JSON_DISABLE_UNLOCKED_FILE_IO`](../macros/json_disable_unlocked_file_io.md) - read a `FILE*` with the locking stdio
functions
- [Parsing](../../features/parsing/index.md) - overview of the parsing functions
- [Comments](../../features/comments.md) - ignore `//` and `/* */` comments while parsing
- [Trailing Commas](../../features/trailing_commas.md) - accept trailing commas in arrays and objects
- [Parser Callbacks](../../features/parsing/parser_callbacks.md) - filter or inspect values while parsing
- [Parsing and Exceptions](../../features/parsing/parse_exceptions.md) - handling parse errors and locating them in the input
- [Parsing Untrusted Input](../../features/parsing/untrusted_input.md) - limits and checks for input you do not control
## Version history
+6 -11
View File
@@ -43,9 +43,6 @@ classDiagram
style json_parse_error fill:#CCCCFF
```
<p class="nj-caption" markdown>Class hierarchy of the library's exceptions; arrows point from a derived class to its
base class, and the highlighted box is `basic_json::parse_error`.</p>
## Member functions
- **what** - returns explanatory string
@@ -78,14 +75,12 @@ or the end of file. This also holds true when reading a byte vector for binary f
## See also
- [`exception`](exception.md) - the base class of all exceptions thrown by the library
- [List of parse errors](../../home/exceptions.md#parse-errors) - overview of parse errors (`parse_error`)
- [`invalid_iterator`](invalid_iterator.md) - exceptions indicating errors with iterators
- [`type_error`](type_error.md) - exceptions indicating executing a member function with a wrong type
- [`out_of_range`](out_of_range.md) - exceptions indicating access out of the defined range
- [`other_error`](other_error.md) - exceptions indicating other library errors
- [Parsing and Exceptions](../../features/parsing/parse_exceptions.md) - handling parse errors and locating them in the input
- [Working Without Exceptions](../../features/no_exceptions.md) - error handling when exceptions are disabled
- [`exception`](exception.md) for the base class of all exceptions thrown by the library
- [List of parse errors](../../home/exceptions.md#parse-errors)
- [`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
## Version history
@@ -22,12 +22,7 @@ The parser callback distinguishes the following events:
## Examples
<div class="nj-fig-wrap" markdown>
--8<-- "images/callback_events.svg"
</div>
<p class="nj-caption" markdown>Each coloured dot marks where the parser reports a `parse_event_t` event while reading
the JSON text on the left; the legend on the right names the event per colour.</p>
![Example when certain parse events are triggered](../../images/callback_events.png)
??? example
@@ -46,9 +41,8 @@ the JSON text on the left; the legend on the right names the event per colour.</
## See also
- [`parser_callback_t`](parser_callback_t.md) - callback function type for the parser
- [`parse`](parse.md) - deserialize from a compatible input
- [Parser Callbacks](../../features/parsing/parser_callbacks.md) - filter or inspect values while parsing
- [parser_callback_t](parser_callback_t.md) callback function type for the parser
- [parse](parse.md) deserialize from a compatible input
## Version history
@@ -23,12 +23,7 @@ table describes the values of the parameters `depth`, `event`, and `parsed`.
| `parse_event_t::array_end` | the parser read `]` and finished processing a JSON array | depth of the parent of the JSON array | the parsed JSON array |
| `parse_event_t::value` | the parser finished reading a JSON value | depth of the value | the parsed JSON value |
<div class="nj-fig-wrap" markdown>
--8<-- "images/callback_events.svg"
</div>
<p class="nj-caption" markdown>Parse events for a small JSON text: each coloured dot marks the position at which the
parser calls the callback, and the legend on the right names the event per colour.</p>
![Example when certain parse events are triggered](../../images/callback_events.png)
Discarding a value (i.e., returning `#!cpp false`) has different effects depending on the context in which function was
called:
@@ -97,9 +92,8 @@ the latter case, it is skipped completely, or replaced by `null` if it is the to
## See also
- [`parse`](parse.md) - deserialize from a compatible input
- [`parse_event_t`](parse_event_t.md) - enumeration of parser events
- [Parser Callbacks](../../features/parsing/parser_callbacks.md) - filter or inspect values while parsing
- [parse](parse.md) deserialize from a compatible input
- [parse_event_t](parse_event_t.md) enumeration of parser events
## Version history
+4 -6
View File
@@ -105,12 +105,10 @@ is kept, see [`object_t`](object_t.md#behavior)), so `#!json {"op": "add", "op":
## See also
- [RFC 6902 (JSON Patch)](https://tools.ietf.org/html/rfc6902) - specification of JSON Patch
- [RFC 6901 (JSON Pointer)](https://tools.ietf.org/html/rfc6901) - specification of JSON Pointer
- [`patch_inplace`](patch_inplace.md) - applies a JSON Patch without creating a copy of the document
- [`merge_patch`](merge_patch.md) - applies a JSON Merge Patch
- [JSON Patch and Diff](../../features/json_patch.md) - the article on JSON Patch
- [JSON Pointer](../../features/json_pointer.md) - the addressing scheme used for patch paths
- [RFC 6902 (JSON Patch)](https://tools.ietf.org/html/rfc6902)
- [RFC 6901 (JSON Pointer)](https://tools.ietf.org/html/rfc6901)
- [patch_inplace](patch_inplace.md) applies a JSON Patch without creating a copy of the document
- [merge_patch](merge_patch.md) applies a JSON Merge Patch
## Version history
@@ -103,11 +103,10 @@ is kept, see [`object_t`](object_t.md#behavior)), so `#!json {"op": "add", "op":
## See also
- [RFC 6902 (JSON Patch)](https://tools.ietf.org/html/rfc6902) - specification of JSON Patch
- [RFC 6901 (JSON Pointer)](https://tools.ietf.org/html/rfc6901) - specification of JSON Pointer
- [`patch`](patch.md) - applies a JSON Patch
- [`merge_patch`](merge_patch.md) - applies a JSON Merge Patch
- [JSON Patch and Diff](../../features/json_patch.md) - the article on JSON Patch
- [RFC 6902 (JSON Patch)](https://tools.ietf.org/html/rfc6902)
- [RFC 6901 (JSON Pointer)](https://tools.ietf.org/html/rfc6901)
- [patch](patch.md) applies a JSON Patch
- [merge_patch](merge_patch.md) applies a JSON Merge Patch
## Version history
+2 -2
View File
@@ -119,8 +119,8 @@ throws.
## See also
- [`emplace_back`](emplace_back.md) - add a value to an array
- [`operator+=`](operator+=.md) - add a value to an array/object
- [emplace_back](emplace_back.md) add a value to an array
- [operator+=](operator+=.md) add a value to an array/object
- [Modifying values](../../features/modifying_values.md) - the article on modifying values
## Version history
+4 -10
View File
@@ -7,13 +7,7 @@ const_reverse_iterator rbegin() const noexcept;
Returns an iterator to the reverse-beginning; that is, the last element.
<div class="nj-fig-wrap" markdown>
--8<-- "images/range-rbegin-rend.svg"
</div>
<p class="nj-caption" markdown>`rbegin()` points to the last element and `rend()` to the position before the first
element. The upper row is the reversed sequence and the lower row the forward sequence; dashed arrows link each reverse
iterator to the forward iterator it stores, and dashed cells are past-the-last positions.</p>
![Illustration from cppreference.com](../../images/range-rbegin-rend.svg)
## Return value
@@ -45,9 +39,9 @@ Constant.
## See also
- [`rend`](rend.md) - returns a reverse iterator to one before the first element
- [`crbegin`](crbegin.md) - returns a const reverse iterator to the last element
- [`begin`](begin.md) - returns an iterator to the first element
- [rend](rend.md) returns a reverse iterator to one before the first element
- [crbegin](crbegin.md) returns a const reverse iterator to the last element
- [begin](begin.md) returns an iterator to the first element
- [Iterators](../../features/iterators.md) - the article on iterators
## Version history
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