Merge branch 'develop' into fix/json_pointer_create_object_5357

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
This commit is contained in:
Niels Lohmann committed 2026-10-07 20:12:05 +02:00
commit b9a581e6d2
132 files changed
+39854 -3884

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@@ -9,10 +9,10 @@ enum class cbor_tag_handler_t
};
```
This enumeration is used in the [`from_cbor`](from_cbor.md) function to choose how to treat tags:
This enumeration is used in [`from_cbor`](from_cbor.md) and [`sax_parse`](sax_parse.md) to choose how to treat tags:
error
: throw a `parse_error` exception in case of a tag
: report a parse error in case of a tag (the `from_cbor` overloads throw a `parse_error` exception by default)
ignore
: ignore tags
+2 -2
View File
@@ -8,7 +8,7 @@ static basic_json diff(const basic_json& source,
Creates a [JSON Patch](http://jsonpatch.com) so that value `source` can be changed into the value `target` by calling
[`patch`](patch.md) function.
For two JSON values `source` and `target`, the following code yields always `#!cpp true`:
For two JSON values `source` and `target`, the following code always yields `#!cpp true`:
```cpp
source.patch(diff(source, target)) == target;
```
@@ -27,7 +27,7 @@ a JSON patch to convert the `source` to `target`
## Exception safety
Strong guarantee: if an exception is thrown, there are no changes in the JSON value.
Strong guarantee: `source` and `target` are never modified.
## Complexity
@@ -120,3 +120,12 @@ Linear in the size of the input.
- Extended container support (1) to include types with lvalue-only ADL `begin`/`end` (matching `std::begin`/`std::end` semantics) in version 3.13.0.
- Extended overload (2) to accept heterogeneous iterator+sentinel pairs (C++20 ranges support) in version 3.13.0.
- Added `error_handler` parameter in version 3.13.0.
!!! warning "Deprecation"
- Overload (2) replaces calls to `from_bjdata` with a pointer and a length as first two parameters, which has been
deprecated in version 3.13.0. This overload will be removed in version 4.0.0. Please replace all calls like
`#!cpp from_bjdata(ptr, len, ...);` with `#!cpp from_bjdata(ptr, ptr+len, ...);`.
You should be warned by your compiler with a `-Wdeprecated-declarations` warning if you are using a deprecated
function.
@@ -106,3 +106,12 @@ Linear in the size of the input.
## Version history
- Added in version 3.13.0.
!!! warning "Deprecation"
- Overload (2) replaces calls to `from_bon8` with a pointer and a length as first two parameters, which has been
deprecated in version 3.13.0. This overload will be removed in version 4.0.0. Please replace all calls like
`#!cpp from_bon8(ptr, len, ...);` with `#!cpp from_bon8(ptr, ptr+len, ...);`.
You should be warned by your compiler with a `-Wdeprecated-declarations` warning if you are using a deprecated
function.
+3
View File
@@ -109,6 +109,9 @@ The class satisfies the following concept requirements:
- **initializer_list_t** - type for initializer lists of `basic_json` values
- [**input_format_t**](input_format_t.md) - type to choose the format to parse
- [**json_sax_t**](../json_sax/index.md) - type for SAX events
- [**with_object_t, with_array_t, with_string_t, with_boolean_t, with_integers_t, with_float_t, with_allocator_t,
with_json_serializer_t, with_binary_t, with_base_class_t**](with_t.md) - types to create a `basic_json` type with
one (or two) replaced template parameters
### Exceptions
@@ -55,6 +55,10 @@ This implementation does exactly follow this approach, as it uses double precisi
smaller than `-1.79769313486232e+308` and values greater than `1.79769313486232e+308` will be stored as NaN internally
and be serialized to `null`.
During deserialization (from JSON text or any of the binary formats), a finite number that does not fit into
`number_float_t` is rejected with [`out_of_range.406`](../../home/exceptions.md#jsonexceptionout_of_range406), for
example a double-precision number in a binary format when `number_float_t` is `#!cpp float`.
### Storage
Floating-point number values are stored directly inside a `basic_json` type.
@@ -47,8 +47,9 @@ With the default values for `NumberIntegerType` (`std::int64_t`), the default va
When the default type is used, the maximal integer number that can be stored is `9223372036854775807` (INT64_MAX) and
the minimal integer number that can be stored is `-9223372036854775808` (INT64_MIN). Integer numbers that are out of
range will yield over/underflow when used in a constructor. During deserialization, too large or small integer numbers
will automatically be stored as [`number_unsigned_t`](number_unsigned_t.md) or [`number_float_t`](number_float_t.md).
range will yield over/underflow when used in a constructor. During deserialization (from JSON text or any of the binary
formats), too large or small integer numbers will automatically be stored as [`number_unsigned_t`](number_unsigned_t.md)
or [`number_float_t`](number_float_t.md).
[RFC 8259](https://tools.ietf.org/html/rfc8259) further states:
> Note that when such software is used, numbers that are integers and are in the range [-2<sup>53</sup>+1, 2<sup>53</sup>-1] are
@@ -48,8 +48,9 @@ With the default values for `NumberUnsignedType` (`std::uint64_t`), the default
When the default type is used, the maximal integer number that can be stored is `18446744073709551615` (UINT64_MAX) and
the minimal integer number that can be stored is `0`. Integer numbers that are out of range will yield over/underflow
when used in a constructor. During deserialization, too large or small integer numbers will automatically be stored
as [`number_integer_t`](number_integer_t.md) or [`number_float_t`](number_float_t.md).
when used in a constructor. During deserialization (from JSON text or any of the binary formats), too large or small
integer numbers will automatically be stored as [`number_integer_t`](number_integer_t.md) or
[`number_float_t`](number_float_t.md).
[RFC 8259](https://tools.ietf.org/html/rfc8259) further states:
> Note that when such software is used, numbers that are integers and are in the range [-2<sup>53</sup>+1, 2<sup>53</sup>-1] are
+10 -3
View File
@@ -8,7 +8,8 @@ static bool sax_parse(InputType&& i,
input_format_t format = input_format_t::json,
const bool strict = true,
const bool ignore_comments = false,
const bool ignore_trailing_commas = false);
const bool ignore_trailing_commas = false,
const cbor_tag_handler_t tag_handler = cbor_tag_handler_t::error);
// (2)
template<class IteratorType, class SAX, class SentinelType = IteratorType>
@@ -17,13 +18,14 @@ static bool sax_parse(IteratorType first, SentinelType last,
input_format_t format = input_format_t::json,
const bool strict = true,
const bool ignore_comments = false,
const bool ignore_trailing_commas = false);
const bool ignore_trailing_commas = false,
const cbor_tag_handler_t tag_handler = cbor_tag_handler_t::error);
```
Read from input and generate SAX events
1. Read from a compatible input.
2. Read from a pair of character iterators, or an iterator and a sentinel of a different type (C++20 ranges support)
2. Read from a pair of character iterators, or an iterator and a sentinel of a different type (C++20 ranges support).
The value_type of the iterator must be an integral type with a size of 1, 2, or 4 bytes, which will be interpreted
respectively as UTF-8, UTF-16, and UTF-32. If `SentinelType` differs from `IteratorType`, it must be comparable to
@@ -82,6 +84,10 @@ The SAX event lister must follow the interface of [`json_sax`](../json_sax/index
: whether trailing commas in arrays or objects should be ignored and treated like whitespace (`#!cpp true`) or yield a parse error
(`#!cpp false`); (optional, `#!cpp false` by default)
`tag_handler` (in)
: how to handle CBOR tags; see [`cbor_tag_handler_t`](cbor_tag_handler_t.md). Ignored for formats other than CBOR
(optional, `cbor_tag_handler_t::error` by default).
`first` (in)
: iterator to the start of a character range
@@ -137,6 +143,7 @@ A UTF-8 byte order mark is silently ignored.
- Added in version 3.2.0.
- Ignoring comments via `ignore_comments` added in version 3.9.0.
- Added `ignore_trailing_commas` in version 3.13.0.
- Added `tag_handler` in version 3.13.0.
- Extended container support (1) to include types with lvalue-only ADL `begin`/`end` (matching `std::begin`/`std::end` semantics) in version 3.13.0.
- Extended overload (2) to accept heterogeneous iterator+sentinel pairs (C++20 ranges support) in version 3.13.0.
- `JSON_PRECISE_STREAM_POSITION` added in version 3.13.0 to optionally leave a `#!cpp std::istream` positioned right
+12 -3
View File
@@ -7,8 +7,14 @@ namespace std {
```
Return a hash value for a JSON object. The hash function tries to rely on `std::hash` where possible. Furthermore, the
type of the JSON value is taken into account to have different hash values for `#!json null`, `#!cpp 0`, `#!cpp 0U`, and
`#!cpp false`, etc.
type of the JSON value is taken into account, so `#!json null`, `#!cpp false`, and numbers may hash differently from
each other. Numbers that compare equal under [`operator==`](operator_eq.md) always hash equally, regardless of
whether they are stored as signed integer, unsigned integer, or floating-point number.
Numbers are hashed by their value converted to `number_float_t`. Converting an integer to `number_float_t` therefore
keeps its hash, but converting a floating-point number to an integer type is lossy and can change it: `#!cpp 0.5`
converts to `#!cpp 0`, which need not have the same hash. Unequal numbers can also share a hash value, for example two
large integers that convert to the same `number_float_t`.
## Examples
@@ -26,7 +32,8 @@ type of the JSON value is taken into account to have different hash values for `
--8<-- "examples/std_hash.output"
```
Note the output is platform-dependent.
The hash values shown are examples only. They depend on the platform, the compiler, and the compiler version, and
they can change between versions of this library. Do not persist them or rely on specific values.
## See also
@@ -36,3 +43,5 @@ type of the JSON value is taken into account to have different hash values for `
- Added in version 1.0.0.
- Extended for arbitrary basic_json types in version 3.10.5.
- Numbers that compare equal hash equally since version 3.13.0; before, `#!cpp 0`, `#!cpp 0U`, and `#!cpp 0.0` had
different hash values.
+5 -1
View File
@@ -68,6 +68,8 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
- Throws [type_error.316](../../home/exceptions.md#jsonexceptiontype_error316) if a string or object key in `j` is
not valid UTF-8 and `error_handler` is `strict` (the default only if
[`JSON_STRICT_BINARY_UTF8`](../macros/json_strict_binary_utf8.md) is enabled)
- Throws [type_error.321](../../home/exceptions.md#jsonexceptiontype_error321) if `j` or a value nested in it is
discarded; example: `"cannot serialize discarded value to BJData"`
## Complexity
@@ -119,4 +121,6 @@ Linear in the size of the JSON value `j`.
- BJData version parameter (for draft3 binary encoding) added in version 3.12.0.
- Added `error_handler` parameter in version 3.13.0. Its default, `keep`, writes the bytes of a string or object key
that is not valid UTF-8 unchanged, as before; `strict` (the default if
[`JSON_STRICT_BINARY_UTF8`](../macros/json_strict_binary_utf8.md) is enabled) throws `type_error.316`.
[`JSON_STRICT_BINARY_UTF8`](../macros/json_strict_binary_utf8.md) is enabled) throws `type_error.316`.
- Throws `type_error.321` for a discarded value since version 3.13.0; previously, a discarded value nested in an
array or object was silently skipped, producing invalid BJData.
@@ -58,6 +58,9 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
- Throws [type_error.316](../../home/exceptions.md#jsonexceptiontype_error316) if a string or object key is
not valid UTF-8 and `error_handler` is `strict` (the default only if
[`JSON_STRICT_BINARY_UTF8`](../macros/json_strict_binary_utf8.md) is enabled)
- Throws [type_error.321](../../home/exceptions.md#jsonexceptiontype_error321) if a value nested in `j` is discarded
(the top-level value itself is covered by `type_error.317` above, since it must be an object); example:
`"cannot serialize discarded value to BSON"`
## Complexity
@@ -110,6 +113,8 @@ pass before anything is written.
- Throws `out_of_range.412` and `out_of_range.415` since version 3.13.0.
- Linear in the size of `j`, and no longer limited by the call stack for deeply nested values, since version 3.13.0.
- `out_of_range.415` is now detected before anything is written, like the other exceptions above, since version 3.13.0.
- Throws `type_error.321` for a discarded value nested in `j` since version 3.13.0; previously, it was silently
skipped, producing a document whose declared size did not match what was actually written.
- Added `error_handler` parameter in version 3.13.0. Its default, `keep`, writes the bytes of a string or object key
that is not valid UTF-8 unchanged, as before; `strict` (the default if
[`JSON_STRICT_BINARY_UTF8`](../macros/json_strict_binary_utf8.md) is enabled) throws `type_error.316` before anything
@@ -49,6 +49,8 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
- Throws [type_error.316](../../home/exceptions.md#jsonexceptiontype_error316) if a string or object key in `j` is
not valid UTF-8 and `error_handler` is `strict` (the default only if
[`JSON_STRICT_BINARY_UTF8`](../macros/json_strict_binary_utf8.md) is enabled)
- Throws [type_error.321](../../home/exceptions.md#jsonexceptiontype_error321) if `j` or a value nested in it is
discarded; example: `"cannot serialize discarded value to CBOR"`
## Complexity
@@ -86,3 +88,5 @@ Linear in the size of the JSON value `j`.
- Added `error_handler` parameter in version 3.13.0. Its default, `keep`, writes the bytes of a string or object key
that is not valid UTF-8 unchanged, as before; `strict` (the default if
[`JSON_STRICT_BINARY_UTF8`](../macros/json_strict_binary_utf8.md) is enabled) throws `type_error.316`.
- Throws `type_error.321` for a discarded value since version 3.13.0; previously, a discarded value nested in an
array or object was silently skipped, producing invalid CBOR.
@@ -54,6 +54,8 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
`"subtype 70000 is too large for the MessagePack ext type (max 255)"`
- Throws [type_error.316](../../home/exceptions.md#jsonexceptiontype_error316) if a string or object key in `j` is
not valid UTF-8 and `error_handler` is `strict`
- Throws [type_error.321](../../home/exceptions.md#jsonexceptiontype_error321) if `j` or a value nested in it is
discarded; example: `"cannot serialize discarded value to MessagePack"`
## Complexity
@@ -108,3 +110,5 @@ Linear in the size of the JSON value `j`.
- Fixed in version 3.13.0 to serialize `number_integer_t`/`number_unsigned_t` pairs of different width correctly;
before, integers could be serialized with the wrong value if `number_integer_t` was narrower than
`number_unsigned_t`.
- Throws `type_error.321` for a discarded value since version 3.13.0; previously, a discarded value nested in an
array or object was silently skipped, producing invalid MessagePack.
@@ -61,6 +61,8 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
- Throws [type_error.316](../../home/exceptions.md#jsonexceptiontype_error316) if a string or object key in `j` is
not valid UTF-8 and `error_handler` is `strict` (the default only if
[`JSON_STRICT_BINARY_UTF8`](../macros/json_strict_binary_utf8.md) is enabled)
- Throws [type_error.321](../../home/exceptions.md#jsonexceptiontype_error321) if `j` or a value nested in it is
discarded; example: `"cannot serialize discarded value to UBJSON"`
## Complexity
@@ -112,3 +114,5 @@ Linear in the size of the JSON value `j`.
- Added `error_handler` parameter in version 3.13.0. Its default, `keep`, writes the bytes of a string or object key
that is not valid UTF-8 unchanged, as before; `strict` (the default if
[`JSON_STRICT_BINARY_UTF8`](../macros/json_strict_binary_utf8.md) is enabled) throws `type_error.316`.
- Throws `type_error.321` for a discarded value since version 3.13.0; previously, a discarded value nested in an
array or object was silently skipped, producing invalid UBJSON.
+136
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@@ -0,0 +1,136 @@
# <small>nlohmann::basic_json::</small>with_t
Member alias templates `with_object_t`, `with_array_t`, `with_string_t`, `with_boolean_t`, `with_integers_t`,
`with_float_t`, `with_allocator_t`, `with_json_serializer_t`, `with_binary_t`, and `with_base_class_t`.
```cpp
template<template<typename, typename, typename...> class ObjectType2>
using with_object_t = basic_json<ObjectType2, ArrayType, StringType, BooleanType,
NumberIntegerType, NumberUnsignedType, NumberFloatType,
AllocatorType, JSONSerializer, BinaryType, CustomBaseClass>;
template<template<typename, typename...> class ArrayType2>
using with_array_t = basic_json<ObjectType, ArrayType2, StringType, BooleanType,
NumberIntegerType, NumberUnsignedType, NumberFloatType,
AllocatorType, JSONSerializer, BinaryType, CustomBaseClass>;
template<class StringType2>
using with_string_t = basic_json<ObjectType, ArrayType, StringType2, BooleanType,
NumberIntegerType, NumberUnsignedType, NumberFloatType,
AllocatorType, JSONSerializer, BinaryType, CustomBaseClass>;
template<class BooleanType2>
using with_boolean_t = basic_json<ObjectType, ArrayType, StringType, BooleanType2,
NumberIntegerType, NumberUnsignedType, NumberFloatType,
AllocatorType, JSONSerializer, BinaryType, CustomBaseClass>;
template<class NumberIntegerType2, class NumberUnsignedType2>
using with_integers_t = basic_json<ObjectType, ArrayType, StringType, BooleanType,
NumberIntegerType2, NumberUnsignedType2, NumberFloatType,
AllocatorType, JSONSerializer, BinaryType, CustomBaseClass>;
template<class NumberFloatType2>
using with_float_t = basic_json<ObjectType, ArrayType, StringType, BooleanType,
NumberIntegerType, NumberUnsignedType, NumberFloatType2,
AllocatorType, JSONSerializer, BinaryType, CustomBaseClass>;
template<template<typename> class AllocatorType2>
using with_allocator_t = basic_json<ObjectType, ArrayType, StringType, BooleanType,
NumberIntegerType, NumberUnsignedType, NumberFloatType,
AllocatorType2, JSONSerializer, BinaryType, CustomBaseClass>;
template<template<typename, typename = void> class JSONSerializer2>
using with_json_serializer_t = basic_json<ObjectType, ArrayType, StringType, BooleanType,
NumberIntegerType, NumberUnsignedType, NumberFloatType,
AllocatorType, JSONSerializer2, BinaryType, CustomBaseClass>;
template<class BinaryType2>
using with_binary_t = basic_json<ObjectType, ArrayType, StringType, BooleanType,
NumberIntegerType, NumberUnsignedType, NumberFloatType,
AllocatorType, JSONSerializer, BinaryType2, CustomBaseClass>;
template<class CustomBaseClass2>
using with_base_class_t = basic_json<ObjectType, ArrayType, StringType, BooleanType,
NumberIntegerType, NumberUnsignedType, NumberFloatType,
AllocatorType, JSONSerializer, BinaryType, CustomBaseClass2>;
```
These member alias templates make it easier to create a `basic_json` type that is identical to the current type except
for one (or, in the case of `with_integers_t`, two) of its [template parameters](index.md#template-parameters).
Spelling out all 11 template parameters of `basic_json` just to change a single one is verbose and error-prone; these
aliases only require the replacement type(s).
with_object_t&lt;ObjectType2&gt;
: replaces `ObjectType`
with_array_t&lt;ArrayType2&gt;
: replaces `ArrayType`
with_string_t&lt;StringType2&gt;
: replaces `StringType`
with_boolean_t&lt;BooleanType2&gt;
: replaces `BooleanType`
with_integers_t&lt;NumberIntegerType2, NumberUnsignedType2&gt;
: replaces both `NumberIntegerType` and `NumberUnsignedType`; the two are combined into a single alias because they
are usually changed together (for instance, when switching to fixed-width integer types)
with_float_t&lt;NumberFloatType2&gt;
: replaces `NumberFloatType`
with_allocator_t&lt;AllocatorType2&gt;
: replaces `AllocatorType`
with_json_serializer_t&lt;JSONSerializer2&gt;
: replaces `JSONSerializer`
with_binary_t&lt;BinaryType2&gt;
: replaces `BinaryType`
with_base_class_t&lt;CustomBaseClass2&gt;
: replaces `CustomBaseClass`; see also [`json_base_class_t`](json_base_class_t.md)
## Notes
All other template parameters are kept unchanged, so the resulting type still uses, for instance, the same
`ObjectType` unless `with_object_t` itself is used.
The aliases are members of every `basic_json` specialization, including [`ordered_json`](../ordered_json.md), and the
type they produce is again a `basic_json` specialization. They can therefore be chained to replace several template
parameters at once:
```cpp
using my_json = nlohmann::json::with_integers_t<int, unsigned int>::with_float_t<float>;
using my_ordered_json = nlohmann::ordered_json::with_string_t<std::wstring>;
```
The result is the same type as spelling out all template parameters, so the order of the chained aliases does not
matter. For instance, `nlohmann::json::with_object_t<nlohmann::ordered_map>` is `nlohmann::ordered_json`.
## Examples
??? example
The following code shows how `with_object_t` can be used to create a JSON type that stores object elements in a
`std::map` and therefore keeps them sorted by key, unlike the default type which preserves insertion order
only when `nlohmann::ordered_json` is used.
```cpp
--8<-- "examples/with_t.cpp"
```
Output:
```json
--8<-- "examples/with_t.output"
```
## See also
- [basic_json](index.md#template-parameters) - the template parameters that can be replaced
- [json_base_class_t](json_base_class_t.md) - the type used for `CustomBaseClass`
## Version history
- Added in version 3.13.0.
+7
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@@ -58,6 +58,13 @@ header. See also the [macro overview page](../../features/macros.md).
- [**JSON_DISABLE_ENUM_SERIALIZATION**](json_disable_enum_serialization.md) - switch off default serialization/deserialization functions for enums
- [**JSON_DISABLE_TUPLE_REFERENCE_CONVERSION**](json_disable_tuple_reference_conversion.md) - switch off conversion from a one-element tuple of a JSON reference
- [**JSON_USE_IMPLICIT_CONVERSIONS**](json_use_implicit_conversions.md) - control implicit conversions
- [**JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS**](json_use_objects_for_enum_keyed_maps.md) - opt in to storing maps with enum
keys as objects
## Deprecated functions
- [**JSON_DELETE_DEPRECATED_FUNCTIONS**](json_delete_deprecated_functions.md) - opt in to deleting the deprecated
functions ahead of their removal in version 4.0.0
## Comparison behavior
@@ -50,9 +50,11 @@ The default value is `0` (disabled — existing behavior is preserved).
```
Code that relies on these producing arrays must use `json::array()` instead (see below). Lists with more than one
element, and a single `[string, value]` pair such as `{{"key", "value"}}`, which still creates an object, are not
affected. The library's own conversions are not affected either: for example, `std::tuple<int>{5}` still becomes
`[5]`.
element, and a single `[string, value]` pair *written as a braced list*, such as `{{"key", "value"}}`, which still
creates an object, are not affected. This exception is based on how the pair is written, not on the shape of its
value: an existing JSON value that happens to be a two-element array with a string as its first element, such as
`json arr = {"key", 42};`, is still copied by `json j{arr};` rather than turned into an object. The library's own
conversions are not affected either: for example, `std::tuple<int>{5}` still becomes `[5]`.
!!! note "ABI compatibility"
@@ -0,0 +1,96 @@
# JSON_DELETE_DEPRECATED_FUNCTIONS
```cpp
#define JSON_DELETE_DEPRECATED_FUNCTIONS /* value */
```
When defined to `1`, all [deprecated functions](../../community/roadmap.md#removal-of-deprecated-functions) of the
library are declared as deleted (`= delete`) instead of only being marked as deprecated. Code that still calls one of
them no longer compiles. This way, you can find all calls that need to be replaced before version 4.0.0 removes these
functions; the [migration guide](../../integration/migration_guide.md#replace-deprecated-functions) describes how.
A deleted function, unlike a removed one, still takes part in overload resolution. A call that would select it
therefore fails to compile instead of silently selecting another overload. This matters for the deprecated
`from_*(ptr, len)` overloads of [`from_cbor`](../basic_json/from_cbor.md), [`from_msgpack`](../basic_json/from_msgpack.md),
[`from_ubjson`](../basic_json/from_ubjson.md), [`from_bjdata`](../basic_json/from_bjdata.md),
[`from_bon8`](../basic_json/from_bon8.md), and [`from_bson`](../basic_json/from_bson.md): without them, a call like
`from_cbor(ptr, len)` would compile, read `ptr` as a NUL-terminated string, and convert `len` to the `strict` parameter.
The macro does not affect the deprecated legacy comparison of discarded values, which is controlled by
[`JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON`](json_use_legacy_discarded_value_comparison.md).
## Default definition
The default value is `0` (disabled, the deprecated functions can still be called, and the compiler warns about it).
```cpp
#define JSON_DELETE_DEPRECATED_FUNCTIONS 0
```
## Notes
!!! info "CMake option"
The macro can also be set with the CMake option
[`JSON_DeleteDeprecatedFunctions`](../../integration/cmake.md#json_deletedeprecatedfunctions) (`OFF` by default).
!!! warning "Opt-in only"
This macro must be defined **before** including `<nlohmann/json.hpp>`. Defining it after the include has no
effect. Define it for the whole project to avoid different declarations of the same class in different
translation units.
!!! note "ABI compatibility"
The macro only turns calls that compile into calls that do not; it does not change the layout or the behavior of
any type. Its value is therefore not encoded in the [namespace](../../features/namespace.md).
## Examples
??? example "Example: default behavior (macro not defined)"
Without the macro, the deprecated overload is called, and the compiler warns about it:
```cpp
#include <nlohmann/json.hpp>
using json = nlohmann::json;
int main()
{
const std::vector<std::uint8_t> v = {0x82, 0x01, 0x02};
auto j = json::from_cbor(v.data(), v.size());
// warning: 'from_cbor' is deprecated: Since 3.8.0; use from_cbor(ptr, ptr + len)
}
```
??? example "Example: deleted deprecated functions (macro defined to 1)"
With the macro, the call does not compile:
```cpp
#define JSON_DELETE_DEPRECATED_FUNCTIONS 1
#include <nlohmann/json.hpp>
using json = nlohmann::json;
int main()
{
const std::vector<std::uint8_t> v = {0x82, 0x01, 0x02};
auto j = json::from_cbor(v.data(), v.size());
// error: call to deleted function 'from_cbor'
}
```
## See also
- [Roadmap: removal of deprecated functions](../../community/roadmap.md#removal-of-deprecated-functions) - the
deprecated functions and the version they were deprecated in
- [Migration guide: replace deprecated functions](../../integration/migration_guide.md#replace-deprecated-functions) -
how to replace each deprecated function
## Version history
- Added in version 3.13.0.
- Planned to be removed in version 4.0.0, which removes the deprecated functions. The deprecated `from_*(ptr, len)`
overloads stay deleted in version 4.0.0.
@@ -112,3 +112,4 @@ The default value is `0` (disabled — existing behavior is preserved).
## Version history
- Added in version 3.13.0.
- Planned to become the default (with the macro removed) in version 4.0.0.
@@ -44,7 +44,7 @@ By default, implicit conversions are enabled.
## Examples
??? example "Example: implicit conversion"
??? example "Example: implicit and explicit conversions"
This is an example for an implicit conversion:
@@ -0,0 +1,139 @@
# JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS
```cpp
#define JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS /* value */
```
When defined to `1`, maps whose keys are enums (such as `std::map<E, T>` or `std::unordered_map<E, T>`) are stored as
JSON objects, using the enum's own conversion for the keys. By default, they are stored as arrays of `[key, value]`
pairs.
## Default definition
The default value is `0` (disabled — existing behavior is preserved).
```cpp
#define JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS 0
```
## Notes
!!! note "Background"
JSON object keys are strings, so a map is only stored as an object if its keys can be converted to a string type.
Enums are not, even if [`NLOHMANN_JSON_SERIALIZE_ENUM`](nlohmann_json_serialize_enum.md) maps them to strings, so a
map with enum keys becomes an array of `[key, value]` pairs:
```json
[["stopped", "aa"], ["completed", "bb"]]
```
With this macro, the same map becomes an object
(see [#4378](https://github.com/nlohmann/json/issues/4378)):
```json
{"completed": "bb", "stopped": "aa"}
```
!!! note "Maps with non-unique keys"
Maps that allow duplicate keys, such as `std::multimap<E, T>` or `std::unordered_multimap<E, T>`, are not affected
by the macro and are still stored as arrays of `[key, value]` pairs, as an object cannot hold duplicate keys.
!!! note "Reading"
Reading is not affected by the macro: a map with enum keys can always be read from both an array of pairs and an
object. For the latter, each key is converted to the enum with its `from_json` function, e.g., the one defined by
[`NLOHMANN_JSON_SERIALIZE_ENUM`](nlohmann_json_serialize_enum.md). Data written without the macro can therefore
still be read after enabling it.
!!! warning "Keys must serialize to distinct strings"
Each key is converted with the enum's `to_json` function. If a key is not converted to a string (for instance, an
enum without [`NLOHMANN_JSON_SERIALIZE_ENUM`](nlohmann_json_serialize_enum.md), which is stored as an integer, or an
enumerator mapped to `nullptr`), [`type_error.302`](../../home/exceptions.md#jsonexceptiontype_error302) is thrown.
If two keys are converted to the same string (for instance, because
[`NLOHMANN_JSON_SERIALIZE_ENUM`](nlohmann_json_serialize_enum.md) maps an unlisted enumerator to the first entry),
[`type_error.318`](../../home/exceptions.md#jsonexceptiontype_error318) is thrown. In both cases, the target value
is not changed.
!!! warning "Opt-in only"
This macro must be defined **before** including `<nlohmann/json.hpp>`. Defining it after the include has no effect.
!!! note "ABI compatibility"
The value of this macro is encoded in the [namespace](../../features/namespace.md) (tag `_ekmo`), resulting in
distinct symbol names. Translation units compiled with and without it can therefore be linked into the same program
without One Definition Rule (ODR) violations, but they cannot exchange instances of library types.
## Examples
??? example "Example: default behavior (macro not defined)"
Without the macro, a map with enum keys is stored as an array of pairs:
```cpp
#include <map>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
enum TaskState { TS_STOPPED, TS_RUNNING, TS_COMPLETED };
NLOHMANN_JSON_SERIALIZE_ENUM(TaskState, {
{TS_STOPPED, "stopped"},
{TS_RUNNING, "running"},
{TS_COMPLETED, "completed"},
})
int main()
{
std::map<TaskState, std::string> m = {{TS_STOPPED, "aa"}, {TS_COMPLETED, "bb"}};
json j = m;
// j is [["stopped","aa"],["completed","bb"]]
}
```
??? example "Example: objects for enum-keyed maps (macro defined to 1)"
With the macro, the same map is stored as an object:
```cpp
#define JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS 1
#include <map>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
enum TaskState { TS_STOPPED, TS_RUNNING, TS_COMPLETED };
NLOHMANN_JSON_SERIALIZE_ENUM(TaskState, {
{TS_STOPPED, "stopped"},
{TS_RUNNING, "running"},
{TS_COMPLETED, "completed"},
})
int main()
{
std::map<TaskState, std::string> m = {{TS_STOPPED, "aa"}, {TS_COMPLETED, "bb"}};
json j = m;
// j is {"completed":"bb","stopped":"aa"}
auto m2 = j.get<std::map<TaskState, std::string>>();
// m2 == m
}
```
## See also
- [Specializing enum conversion](../../features/enum_conversion.md)
- [**NLOHMANN_JSON_SERIALIZE_ENUM**](nlohmann_json_serialize_enum.md) - serialize/deserialize an enum
- [**NLOHMANN_JSON_SERIALIZE_ENUM_STRICT**](nlohmann_json_serialize_enum_strict.md) - serialize/deserialize an enum with
exceptions
## Version history
- Added in version 3.13.0.
@@ -41,6 +41,9 @@ inline void from_json(const BasicJsonType& j, type& e);
conversion. Select this default pair carefully. See example 1 below.
- If an enum or JSON value is specified in multiple conversions, the first matching conversion from the top of the
list will be returned when converting to or from JSON. See example 2 below.
- Maps with enum keys (e.g., `std::map<ENUM_TYPE, T>`) are stored as arrays of `[key, value]` pairs by default.
Define [`JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS`](json_use_objects_for_enum_keyed_maps.md) to store them as objects
with the converted keys. Such maps can be read from both forms.
## Examples
@@ -80,6 +83,7 @@ inline void from_json(const BasicJsonType& j, type& e);
- [Specializing enum conversion](../../features/enum_conversion.md)
- [`NLOHMANN_JSON_SERIALIZE_ENUM_STRICT`](./nlohmann_json_serialize_enum_strict.md)
- [`JSON_DISABLE_ENUM_SERIALIZATION`](json_disable_enum_serialization.md)
- [`JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS`](json_use_objects_for_enum_keyed_maps.md)
## Version history
@@ -44,6 +44,9 @@ inline void from_json(const BasicJsonType& j, type& e);
`"enum value out of range for <type>"`.
- If an enum or JSON value is specified in multiple conversions, the first matching conversion from the top of the
list will be returned when converting to or from JSON. See example 2 below.
- Maps with enum keys (e.g., `std::map<ENUM_TYPE, T>`) are stored as arrays of `[key, value]` pairs by default.
Define [`JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS`](json_use_objects_for_enum_keyed_maps.md) to store them as objects
with the converted keys. Such maps can be read from both forms.
## Examples
@@ -99,6 +102,7 @@ inline void from_json(const BasicJsonType& j, type& e);
- [Specializing enum conversion](../../features/enum_conversion.md)
- [`NLOHMANN_JSON_SERIALIZE_ENUM`](./nlohmann_json_serialize_enum.md)
- [`JSON_DISABLE_ENUM_SERIALIZATION`](json_disable_enum_serialization.md)
- [`JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS`](json_use_objects_for_enum_keyed_maps.md)
## Version history
@@ -21,17 +21,18 @@ Note: Some modern features (like C++20 ranges or filesystem support) may be disa
| Compiler | Architecture | Operating System | CI |
|----------------------------------------------|--------------|-----------------------------------|-----------|
| AppleClang 15.0.0.15000040; Xcode 15.0.1 | arm64 | macOS 14.7.2 (Sonoma) | GitHub |
| AppleClang 15.0.0.15000100; Xcode 15.1 | arm64 | macOS 14.7.2 (Sonoma) | GitHub |
| AppleClang 15.0.0.15000100; Xcode 15.2 | arm64 | macOS 14.7.2 (Sonoma) | GitHub |
| AppleClang 15.0.0.15000309; Xcode 15.3 | arm64 | macOS 14.7.2 (Sonoma) | GitHub |
| AppleClang 15.0.0.15000309; Xcode 15.4 | arm64 | macOS 14.7.2 (Sonoma) | GitHub |
| AppleClang 16.0.0.16000026; Xcode 16 | arm64 | macOS 15.2 (Sequoia) | GitHub |
| AppleClang 16.0.0.16000026; Xcode 16.1 | arm64 | macOS 15.2 (Sequoia) | GitHub |
| AppleClang 16.0.0.16000026; Xcode 16.2 | arm64 | macOS 15.2 (Sequoia) | GitHub |
| AppleClang 17.0.0.17000013; Xcode 16.3 | arm64 | macOS 15.5 (Sequoia) | GitHub |
| AppleClang 17.0.0.17000013; Xcode 16.4 | arm64 | macOS 15.5 (Sequoia) | GitHub |
| AppleClang 17.0.0.17000319; Xcode 26.0.1 | arm64 | macOS 15.5 (Sequoia) | GitHub |
| AppleClang 17.0.0.17000404; Xcode 26.1.1 | arm64 | macOS 15.7.9 (Sequoia) | GitHub |
| AppleClang 17.0.0.17000603; Xcode 26.2 | arm64 | macOS 15.7.9 (Sequoia) | GitHub |
| AppleClang 17.0.0.17000604; Xcode 26.3 | arm64 | macOS 15.7.9 (Sequoia) | GitHub |
| AppleClang 21.0.0.21000099; Xcode 26.4.1 | arm64 | macOS 26.6.2 (Tahoe) | GitHub |
| AppleClang 21.0.0.21000101; Xcode 26.5 | arm64 | macOS 26.6.2 (Tahoe) | GitHub |
| AppleClang 21.0.0.21000101; Xcode 26.6 | arm64 | macOS 26.6.2 (Tahoe) | GitHub |
| Clang 3.4.2 | x86_64 | Ubuntu 22.04.1 LTS | GitHub |
| Clang 3.5.2 | x86_64 | Ubuntu 22.04.1 LTS | GitHub |
| Clang 3.6.2 | x86_64 | Ubuntu 22.04.1 LTS | GitHub |
@@ -89,7 +90,7 @@ Note: Some modern features (like C++20 ranges or filesystem support) may be disa
| GNU 13.3.0 | x86_64 | Ubuntu 22.04.1 LTS | GitHub |
| GNU 14.2.0 | x86_64 | Ubuntu 22.04.1 LTS | GitHub |
| GNU 15.1.0 | x86_64 | Ubuntu 22.04.1 LTS | GitHub |
| GNU 16.1.0 | x86_64 | Ubuntu 22.04.1 LTS | GitHub |
| GNU 16.2.0 | x86_64 | Ubuntu 22.04.1 LTS | GitHub |
| GNU 16.1.0 | arm64 | Ubuntu 24.04 | GitHub |
| icpc (ICC) 2021.10.0 20230609 | x86_64 | Ubuntu 22.04 LTS | GitHub |
| icpx (Intel oneAPI DPC++/C++) 2025.3.2 | x86_64 | Ubuntu 24.04 LTS | GitHub |
+39 -5
View File
@@ -25,9 +25,7 @@ work items are tracked in the [GitHub milestones](https://github.com/nlohmann/js
## What the project will not do
- **Break the public API of version 3.x.** See the
[contribution guidelines](https://github.com/nlohmann/json/blob/develop/.github/CONTRIBUTING.md#break-the-public-api)
for what counts as a breaking change.
- **Break the public API of version 3.x.** See [API stability](#api-stability) for what this covers.
- **Require a newer C++ standard than C++11.**
- **Break JSON conformance** or enable non-standard extensions by default.
- **Add dependencies** or require a build step. The library remains header-only, and the single header
@@ -35,6 +33,32 @@ work items are tracked in the [GitHub milestones](https://github.com/nlohmann/js
- **Trade simplicity for speed or memory efficiency.** Performance improvements are welcome, but the library is not
meant to compete with the fastest JSON libraries, see [Design goals](../home/design_goals.md).
## API stability
Releases follow [semantic versioning](https://semver.org): a minor or patch release of version 3.x does not break code
that uses the public API. In particular, a 3.x release does not:
- change the signature of a function (its parameter types, return type, number of parameters, or the const-ness of a
member function);
- remove or rename a function or class;
- change which exceptions a function throws, or the [exception ids](../home/exceptions.md);
- change access specifiers or default arguments.
Exceptions to these rules, for instance when fixing a bug requires changing the exception a function throws, are
documented in the [release notes](../home/releases.md).
The following are **not** part of the public API and may change in any release, including patch releases:
- The text of exception messages returned by `what()`. Use the [exception id](../home/exceptions.md) to tell errors
apart.
- The ABI, including `sizeof(basic_json)` and the memory layout of its values. Recompile your code when you upgrade the
library. The [versioned inline namespace](../features/namespace.md) turns mixing versions into a link error.
- Everything in namespace `nlohmann::detail`, and macros and type traits that are not documented in the
[API reference](../api/basic_json/index.md).
Changes that would break the public API are only added behind a macro whose default keeps the 3.x behavior, see
[Version 4.0](#version-40).
## Version 4.0
There is no release date for version 4.0 yet. Proposals that need a major version, for instance stricter type
@@ -64,6 +88,8 @@ The following macros guard changes that are planned to become the default in ver
| [`JSON_PRECISE_STREAM_POSITION`](../api/macros/json_precise_stream_position.md) | `0` | `1`: reading from a stream does not consume the character after a number | – | 3.13.0 |
| [`JSON_STRICT_NUL_HANDLING`](../api/macros/json_strict_nul_handling.md) | `0` | `1`: a NUL byte in the input is a parse error instead of the end of input | [`JSON_StrictNulHandling`](../integration/cmake.md#json_strictnulhandling) | 3.13.0 |
| [`JSON_STRICT_BINARY_UTF8`](../api/macros/json_strict_binary_utf8.md) | `0` | `1`: `to_cbor`, `to_ubjson`, `to_bjdata`, and `to_bson` throw for strings that are not valid UTF-8 by default | [`JSON_StrictBinaryUTF8`](../integration/cmake.md#json_strictbinaryutf8) | 3.13.0 |
| [`JSON_DISABLE_TUPLE_REFERENCE_CONVERSION`](../api/macros/json_disable_tuple_reference_conversion.md) | `0` | `1`: a `basic_json` value can no longer be created from a one-element tuple of a reference to it, such as `std::forward_as_tuple(j)`| [`JSON_DisableTupleReferenceConversion`](../integration/cmake.md#json_disabletuplereferenceconversion) | 3.13.0 |
| [`JSON_DELETE_DEPRECATED_FUNCTIONS`](../api/macros/json_delete_deprecated_functions.md) | `0` | removed: the deprecated functions are removed (see below); the `from_*(ptr, len)` overloads stay deleted | [`JSON_DeleteDeprecatedFunctions`](../integration/cmake.md#json_deletedeprecatedfunctions) | 3.13.0 |
For example, the following makes a 3.x release behave like version 4.0 with respect to these changes:
@@ -75,6 +101,8 @@ For example, the following makes a 3.x release behave like version 4.0 with resp
#define JSON_PRECISE_STREAM_POSITION 1
#define JSON_STRICT_NUL_HANDLING 1
#define JSON_STRICT_BINARY_UTF8 1
#define JSON_DISABLE_TUPLE_REFERENCE_CONVERSION 1
#define JSON_DELETE_DEPRECATED_FUNCTIONS 1
#include <nlohmann/json.hpp>
```
@@ -84,8 +112,13 @@ way to achieve this.
### Removal of deprecated functions
Version 4.0 will remove all deprecated functions. Compiling with deprecation warnings enabled shows which of them your
code still uses. The [migration guide](../integration/migration_guide.md#replace-deprecated-functions) shows how to
replace each of them.
code still uses. Defining [`JSON_DELETE_DEPRECATED_FUNCTIONS`](../api/macros/json_delete_deprecated_functions.md) to
`1` turns these warnings into errors, as the deprecated functions are then deleted. The
[migration guide](../integration/migration_guide.md#replace-deprecated-functions) shows how to replace each of them.
The `from_*` overloads taking a pointer and a length are not removed in version 4.0, but stay deleted. Without them, a
call like `from_cbor(ptr, len)` would still compile: it would read `ptr` as a NUL-terminated string and convert `len`
to the `strict` parameter.
| Deprecated | Since | Migration |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------|----------------------------------------------------------------------------------|
@@ -97,6 +130,7 @@ replace each of them.
| [`json_pointer::operator string_t`](../api/json_pointer/operator_string_t.md) | 3.11.0 | [JSON Pointers](../integration/migration_guide.md#json-pointers) |
| [`json_pointer`](../api/json_pointer/index.md) with a `basic_json` type as template argument, and the overloads of `value`, `contains`, `operator[]`, and `at` accepting such a pointer | 3.11.0 | [JSON Pointers](../integration/migration_guide.md#json-pointers) |
| Comparing a [`json_pointer`](../api/json_pointer/index.md) with a string via [`operator==`](../api/json_pointer/operator_eq.md) or [`operator!=`](../api/json_pointer/operator_ne.md) | 3.11.2 | [JSON Pointers](../integration/migration_guide.md#json-pointers) |
| [`from_bjdata`](../api/basic_json/from_bjdata.md) and [`from_bon8`](../api/basic_json/from_bon8.md) with `(ptr, len)` | 3.13.0 | [Parsing](../integration/migration_guide.md#parsing) |
The deprecated legacy comparison of discarded values is controlled by a macro and therefore listed in the table above.
@@ -13,19 +13,7 @@ class visitor_adaptor_with_metadata
void do_visit(const Ptr& ptr, const Fnc& fnc) const;
};
using json = nlohmann::basic_json <
std::map,
std::vector,
std::string,
bool,
std::int64_t,
std::uint64_t,
double,
std::allocator,
nlohmann::adl_serializer,
std::vector<std::uint8_t>,
visitor_adaptor_with_metadata
>;
using json = nlohmann::json::with_base_class_t<visitor_adaptor_with_metadata>;
template <class Fnc>
void visitor_adaptor_with_metadata::visit(const Fnc& fnc) const
+1
View File
@@ -11,6 +11,7 @@ int main()
<< "hash(false) = " << std::hash<json> {}(json(false)) << '\n'
<< "hash(0) = " << std::hash<json> {}(json(0)) << '\n'
<< "hash(0U) = " << std::hash<json> {}(json(0U)) << '\n'
<< "hash(0.0) = " << std::hash<json> {}(json(0.0)) << '\n'
<< "hash(\"\") = " << std::hash<json> {}(json("")) << '\n'
<< "hash({}) = " << std::hash<json> {}(json::object()) << '\n'
<< "hash([]) = " << std::hash<json> {}(json::array()) << '\n'
+5 -4
View File
@@ -1,8 +1,9 @@
hash(null) = 2654435769
hash(false) = 2654436030
hash(0) = 2654436095
hash(0U) = 2654436156
hash("") = 6142509191626859748
hash(0) = 2654436221
hash(0U) = 2654436221
hash(0.0) = 2654436221
hash("") = 11160318156688833227
hash({}) = 2654435832
hash([]) = 2654435899
hash({"hello": "world"}) = 4469488738203676328
hash({"hello": "world"}) = 3701319991624763853
+18
View File
@@ -0,0 +1,18 @@
#include <iostream>
#include <map>
#include <nlohmann/json.hpp>
// a JSON type that stores objects in a std::map (which keeps keys sorted)
// instead of the default ordered associative container
using sorted_json = nlohmann::json::with_object_t<std::map>;
int main()
{
sorted_json j;
j["c"] = 1;
j["a"] = 2;
j["b"] = 3;
// keys are sorted, because std::map is used to store the object
std::cout << j.dump() << std::endl;
}
+1
View File
@@ -0,0 +1 @@
{"a":2,"b":3,"c":1}
@@ -141,8 +141,14 @@ The library uses the following mapping from JSON values types to BJData types ac
parsed back as a regular array,
- every entry of `"_ArraySize_"` is a positive integer, and their product is representable as a `std::size_t`,
- `"_ArrayData_"` is an array holding exactly that many elements, and
- every element of `"_ArrayData_"` is a number of the kind named by `"_ArrayType_"` (a floating-point number for
`single` and `double`, an integer otherwise).
- every element of `"_ArrayData_"` is a number of the kind named by `"_ArrayType_"`: for the integer types, a
value that fits the named width; for `double`, any value; for `single`, a value that survives narrowing to
`float` and back without change (for instance, `0.1` does not, since it is not exactly representable as
`float`).
An annotated object is always read back with its keys in the order shown above, `"_ArrayType_"`, `"_ArraySize_"`,
`"_ArrayData_"`, regardless of the order the ND-array's header stores them in on the wire. This matters for
`ordered_json`, whose comparison takes key order into account.
The current version of this library does not yet support automatic detection of and conversion from a nested JSON
array input to a BJData ND-array.
@@ -131,6 +131,7 @@ The library maps CBOR types to JSON value types as follows:
| Byte string | binary | 0x59 |
| Byte string | binary | 0x5A |
| Byte string | binary | 0x5B |
| Byte string | binary | 0x5F |
| UTF-8 string | string | 0x60..0x77 |
| UTF-8 string | string | 0x78 |
| UTF-8 string | string | 0x79 |
@@ -156,6 +157,9 @@ The library maps CBOR types to JSON value types as follows:
| Single-Precision Float | number_float | 0xFA |
| Double-Precision Float | number_float | 0xFB |
Indefinite-length UTF-8 strings (0x7F) and byte strings (0x5F) are supported. Each chunk must be a definite-length
string of the same major type, as required by [RFC 8949, Section 3.2.3](https://www.rfc-editor.org/rfc/rfc8949.html#section-3.2.3).
!!! warning "Incomplete mapping"
The mapping is **incomplete** in the sense that not all CBOR types can be converted to a JSON value. The following CBOR types are not supported and will yield parse errors:
@@ -168,9 +172,9 @@ The library maps CBOR types to JSON value types as follows:
!!! warning "Negative integer overflow"
CBOR negative integers (major type 1) are decoded as `-1 - n`. If the encoded magnitude `n` is too large for the
result to fit into `number_integer_t` (`std::int64_t` by default), parsing fails with a
[`parse_error.112`](../../home/exceptions.md#jsonexceptionparse_error112) exception rather than overflowing
silently.
result to fit into `number_integer_t` (`std::int64_t` by default), the result is stored as `number_float_t`, like
a too small integer in JSON text. For example, `-18446744073709551616` (`0x3B` followed by eight `0xFF` bytes) is
stored as `-1.8446744073709552e+19`.
!!! warning "Object keys"
@@ -58,6 +58,23 @@ assert(jPi.get<TaskState>() == TS_INVALID );
--8<-- "examples/nlohmann_json_serialize_enum.output"
```
## Maps with enum keys
By default, maps with enum keys, such as `std::map<TaskState, std::string>`, are stored as arrays of `[key, value]`
pairs, because JSON object keys must be strings. Define
[`JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS`](../api/macros/json_use_objects_for_enum_keyed_maps.md) before including the
library to store them as objects, with the keys converted by the enum's `to_json()` function:
```cpp
std::map<TaskState, std::string> m = {{TS_STOPPED, "aa"}, {TS_COMPLETED, "bb"}};
json j = m;
// default: [["stopped","aa"],["completed","bb"]]
// with JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS: {"completed":"bb","stopped":"aa"}
```
Either form can be read back, with or without the macro.
## Notes
Just as in [Arbitrary Type Conversions](arbitrary_types.md) above,
+20 -1
View File
@@ -23,6 +23,17 @@ This macro overrides [`#!cpp catch`](https://en.cppreference.com/w/cpp/language/
See [full documentation of `JSON_CATCH_USER(exception)`](../api/macros/json_throw_user.md).
## `JSON_DELETE_DEPRECATED_FUNCTIONS`
When defined to `1`, all deprecated functions are declared as deleted instead of only being marked as deprecated, so
code that still calls them no longer compiles. This way, you can find all calls that need to be replaced before version
4.0.0 removes these functions.
The macro can also be set with the CMake option
[`JSON_DeleteDeprecatedFunctions`](../integration/cmake.md#json_deletedeprecatedfunctions) (`OFF` by default).
See [full documentation of `JSON_DELETE_DEPRECATED_FUNCTIONS`](../api/macros/json_delete_deprecated_functions.md).
## `JSON_DIAGNOSTICS`
This macro enables extended diagnostics for exception messages. Possible values are `1` to enable or `0` to disable
@@ -86,7 +97,8 @@ See [full documentation of `JSON_DISABLE_ENUM_SERIALIZATION`](../api/macros/json
## `JSON_DISABLE_TUPLE_REFERENCE_CONVERSION`
When defined to `1`, a JSON value can no longer be created from a one-element `std::tuple` holding a reference to a JSON
value, such as the result of `std::forward_as_tuple(j)`. This lets `std::tuple` convert such tuples element-wise.
value, such as the result of `std::forward_as_tuple(j)`. This lets `std::tuple` convert such tuples element-wise. This
is planned to become the default in version 4.0.0.
See [full documentation of `JSON_DISABLE_TUPLE_REFERENCE_CONVERSION`](../api/macros/json_disable_tuple_reference_conversion.md).
@@ -198,6 +210,13 @@ default.
See [full documentation of `JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON`](../api/macros/json_use_legacy_discarded_value_comparison.md).
## `JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS`
When defined to `1`, maps with enum keys (e.g., `std::map<E, T>`) are stored as objects, using the enum's conversion for
the keys, instead of arrays of `[key, value]` pairs. It is switched off (`0`) by default.
See [full documentation of `JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS`](../api/macros/json_use_objects_for_enum_keyed_maps.md).
## `JSON_USE_SIMDUTF`
When defined, UTF-8 validation of JSON strings read from contiguous byte input is delegated to the
+2
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@@ -21,6 +21,8 @@ The complete default namespace name is derived as follows:
- [`JSON_PRECISE_STREAM_POSITION`](../api/macros/json_precise_stream_position.md) defined non-zero appends `_psp`.
- [`JSON_STRICT_NUL_HANDLING`](../api/macros/json_strict_nul_handling.md) defined non-zero appends `_snul`.
- [`JSON_STRICT_BINARY_UTF8`](../api/macros/json_strict_binary_utf8.md) defined non-zero appends `_sbu8`.
- [`JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS`](../api/macros/json_use_objects_for_enum_keyed_maps.md) defined non-zero
appends `_ekmo`.
- The inline namespace ends with the suffix `_v` followed by the 3 components of the version number separated by
underscores. To omit the version component, see [Disabling the version component](#disabling-the-version-component)
below.
@@ -64,6 +64,7 @@ serialization fails by default. The fourth argument of `dump` selects an
- `strict` (default) — throw a [`type_error.316`](../home/exceptions.md#jsonexceptiontype_error316) exception.
- `replace` — replace invalid bytes with the Unicode replacement character U+FFFD (`�`).
- `ignore` — silently drop invalid bytes.
- `keep` — copy invalid bytes to the output unchanged; the result is not valid UTF-8.
??? example "Example: serialize invalid UTF-8 with different error handlers"
+38 -5
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@@ -331,9 +331,6 @@ An unexpected byte was read in a [binary format](../features/binary_formats/inde
[json.exception.parse_error.112] parse error at byte 15: syntax error while parsing BSON binary: byte array length cannot be negative, is -1
```
```
[json.exception.parse_error.112] parse error at byte 9: syntax error while parsing CBOR value: negative integer overflow
```
```
[json.exception.parse_error.112] parse error at byte 5: syntax error while parsing BSON document: document size 6 does not match the number of bytes read (5)
```
@@ -599,6 +596,9 @@ During implicit or explicit value conversion, the JSON type must be compatible w
[json.exception.type_error.302] type must be string, but is object
```
This exception is also thrown with [`JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS`](../api/macros/json_use_objects_for_enum_keyed_maps.md)
if a key of a map with enum keys is not converted to a string, for instance, because the enum is stored as an integer.
### json.exception.type_error.303
To retrieve a reference to a value stored in a `basic_json` object with `get_ref`, the type of the reference must match the value type. For instance, for a JSON array, the `ReferenceType` must be `array_t &`.
@@ -771,6 +771,7 @@ as well for a string value or object key that is not valid UTF-8 if their `error
- Pass an error handler as last parameter to the `dump()` function to avoid this exception:
- `json::error_handler_t::replace` will replace invalid bytes sequences with `U+FFFD`
- `json::error_handler_t::ignore` will silently ignore invalid byte sequences
- `json::error_handler_t::keep` will copy invalid byte sequences to the output unchanged
### json.exception.type_error.317
@@ -791,6 +792,33 @@ The dynamic type of the object cannot be represented in the requested serializat
Encapsulate the JSON value in an object. That is, instead of serializing `#!json true`, serialize `#!json {"value": true}`
### json.exception.type_error.318
With [`JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS`](../api/macros/json_use_objects_for_enum_keyed_maps.md), a map with enum
keys is stored as an object. This exception is thrown if two of its keys are converted to the same string, so one of the
entries would be lost. This happens, for instance, if [`NLOHMANN_JSON_SERIALIZE_ENUM`](../api/macros/nlohmann_json_serialize_enum.md)
does not list an enumerator and it is therefore converted like the first listed one.
!!! failure "Example message"
```
[json.exception.type_error.318] duplicate object key 'red'
```
### json.exception.type_error.321
A discarded value (one created by [`parse()`](../api/basic_json/parse.md) with a callback that returns `false` for the
value, or by default-constructing a [`basic_json`](../api/basic_json/index.md) with
[`value_t::discarded`](../api/basic_json/value_t.md)) was passed to a binary serialization function, either directly or
nested in an array or object. There is no way to represent a discarded value in CBOR, MessagePack, UBJSON, BJData, or BSON.
!!! failure "Example message"
Serializing `#!json [1, 2]` to CBOR, where the second element was discarded by a parser callback:
```
[json.exception.type_error.321] cannot serialize discarded value to CBOR
```
## Out of range
This exception is thrown in case a library function is called on an input parameter that exceeds the expected range, for instance, in the case of array indices or nonexisting object keys.
@@ -863,13 +891,18 @@ The JSON Patch operations 'remove' and 'add' cannot be applied to the root eleme
### json.exception.out_of_range.406
A parsed number could not be stored as without changing it to NaN or INF.
A parsed number could not be stored without changing it to NaN or INF. For the binary formats, this happens when a
finite floating-point number does not fit into [`number_float_t`](../api/basic_json/number_float_t.md), for example a
double-precision number when `number_float_t` is `#!cpp float`.
!!! failure "Example message"
!!! failure "Example messages"
```
number overflow parsing '10E1000'
```
```
[json.exception.out_of_range.406] syntax error while parsing CBOR value: number overflow
```
### json.exception.out_of_range.407
+1 -1
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@@ -85,7 +85,7 @@ The library supports **Unicode input** as follows:
- The library will not replace [Unicode noncharacters](http://www.unicode.org/faq/private_use.html#nonchar1).
- Invalid surrogates (e.g., incomplete pairs such as `\uDEAD`) will yield parse errors.
- The strings stored in the library are UTF-8 encoded. When using the default string type (`std::string`), note that its length/size functions return the number of stored bytes rather than the number of characters or glyphs.
- When you store strings with different encodings in the library, calling [`dump()`](../api/basic_json/dump.md) may throw an exception unless `json::error_handler_t::replace` or `json::error_handler_t::ignore` are used as error handlers.
- When you store strings with different encodings in the library, calling [`dump()`](../api/basic_json/dump.md) may throw an exception unless `json::error_handler_t::replace`, `json::error_handler_t::ignore`, or `json::error_handler_t::keep` are used as error handlers.
In most cases, the parser is right to complain, because the input is not UTF-8 encoded. This is especially true for Microsoft Windows, where Latin-1 or ISO 8859-1 is often the standard encoding.
+7 -1
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@@ -126,12 +126,18 @@ automatically download a release as a dependency at configure time.
### `JSON_BuildTests`
Build the unit tests when [`BUILD_TESTING`](https://cmake.org/cmake/help/latest/command/enable_testing.html) is enabled. This option is `ON` by default if the library's CMake project is the top project. That is, when integrating the library as described above, the test suite is not built unless explicitly switched on with this option.
Build the unit tests when [`BUILD_TESTING`](https://cmake.org/cmake/help/latest/command/enable_testing.html) is enabled. This option is `ON` by default if the library's CMake project is the top project and the `tests` directory exists (the release archive `json.tar.xz` does not contain it). That is, when integrating the library as described above, the test suite is not built unless explicitly switched on with this option.
### `JSON_CI`
Enable CI build targets. The exact targets are used during the several CI steps and are subject to change without notice. This option is `OFF` by default.
### `JSON_DeleteDeprecatedFunctions`
Delete the deprecated functions instead of only deprecating them by defining the macro
[`JSON_DELETE_DEPRECATED_FUNCTIONS`](../api/macros/json_delete_deprecated_functions.md). This option is `OFF` by
default.
### `JSON_Diagnostics`
Enable [extended diagnostic messages](../home/exceptions.md#extended-diagnostic-messages) by defining macro [`JSON_DIAGNOSTICS`](../api/macros/json_diagnostics.md). This option is `OFF` by default.
@@ -14,6 +14,13 @@ deprecations are annotated with
[`HEDLEY_DEPRECATED_FOR`](https://nemequ.github.io/hedley/api-reference.html#HEDLEY_DEPRECATED_FOR) to report which
function to use instead.
!!! tip "Find all calls of deprecated functions"
Define [`JSON_DELETE_DEPRECATED_FUNCTIONS`](../api/macros/json_delete_deprecated_functions.md) to `1` (or set the
CMake option [`JSON_DeleteDeprecatedFunctions`](cmake.md#json_deletedeprecatedfunctions)) to delete all deprecated
functions. Every remaining call then fails to compile, even if deprecation warnings are disabled, so your code is
ready for version 4.0.0 once it compiles with the macro.
### Parsing
- Function `friend std::istream& operator<<(basic_json&, std::istream&)` is deprecated since 3.0.0. Please use
@@ -41,8 +48,10 @@ function to use instead.
[`from_ubjson`](../api/basic_json/from_ubjson.md), and [`from_bson`](../api/basic_json/from_bson.md)) via initializer
lists is deprecated since 3.8.0. Instead, pass two iterators; for instance, call `from_cbor(ptr, ptr+len)` instead of
`from_cbor({ptr, len})`. Likewise, passing a pointer and a length as two separate arguments to `from_cbor`,
`from_msgpack`, `from_ubjson`, and `from_bson` is deprecated since 3.8.0; call `from_cbor(ptr, ptr+len)` instead of
`from_cbor(ptr, len)`.
`from_msgpack`, `from_ubjson`, and `from_bson` is deprecated since 3.8.0, and to
[`from_bjdata`](../api/basic_json/from_bjdata.md) and [`from_bon8`](../api/basic_json/from_bon8.md) since 3.13.0; call
`from_cbor(ptr, ptr+len)` instead of `from_cbor(ptr, len)`. These overloads will not be removed in version 4.0.0, but
deleted, so a call like `from_cbor(ptr, len)` cannot compile and convert `len` to the `strict` parameter.
=== "Deprecated"
+3
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@@ -232,6 +232,7 @@ nav:
- 'update': api/basic_json/update.md
- 'value': api/basic_json/value.md
- 'value_t': api/basic_json/value_t.md
- 'with_t': api/basic_json/with_t.md
- byte_container_with_subtype:
- 'Overview': api/byte_container_with_subtype/index.md
- '(constructor)': api/byte_container_with_subtype/byte_container_with_subtype.md
@@ -292,6 +293,7 @@ nav:
- 'JSON_BRACE_INIT_COPY_SEMANTICS': api/macros/json_brace_init_copy_semantics.md
- 'JSON_CATCH_USER, JSON_THROW_USER, JSON_TRY_USER': api/macros/json_throw_user.md
- 'JSON_DIAGNOSTICS': api/macros/json_diagnostics.md
- 'JSON_DELETE_DEPRECATED_FUNCTIONS': api/macros/json_delete_deprecated_functions.md
- 'JSON_DIAGNOSTIC_POSITIONS': api/macros/json_diagnostic_positions.md
- 'JSON_DISABLE_ENUM_SERIALIZATION': api/macros/json_disable_enum_serialization.md
- 'JSON_DISABLE_TUPLE_REFERENCE_CONVERSION': api/macros/json_disable_tuple_reference_conversion.md
@@ -313,6 +315,7 @@ nav:
- 'JSON_USE_GLOBAL_UDLS': api/macros/json_use_global_udls.md
- 'JSON_USE_IMPLICIT_CONVERSIONS': api/macros/json_use_implicit_conversions.md
- 'JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON': api/macros/json_use_legacy_discarded_value_comparison.md
- 'JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS': api/macros/json_use_objects_for_enum_keyed_maps.md
- 'JSON_USE_SIMDUTF': api/macros/json_use_simdutf.md
- 'NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE, NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_WITH_DEFAULT, NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE_ONLY_SERIALIZE, NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE, NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_WITH_DEFAULT, NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_ONLY_SERIALIZE': api/macros/nlohmann_define_derived_type.md
- 'NLOHMANN_DEFINE_TYPE_INTRUSIVE, NLOHMANN_DEFINE_TYPE_INTRUSIVE_WITH_DEFAULT, NLOHMANN_DEFINE_TYPE_INTRUSIVE_ONLY_SERIALIZE': api/macros/nlohmann_define_type_intrusive.md
+1 -1
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@@ -6,7 +6,7 @@ mkdocs-material==9.7.7 # theme for mkdocs
mkdocs-material-extensions==1.3.1 # extensions
mkdocs-minify-plugin==0.8.0 # plugin "minify"
mkdocs-redirects==1.2.3 # plugin "redirects"
mkdocs-htmlproofer-plugin==1.5.0 # plugin "htmlproofer"
mkdocs-htmlproofer-plugin==1.6.0 # plugin "htmlproofer"
mkdocs-llmstxt==0.5.0 # plugin "llmstxt"
PyYAML==6.0.3 # linter
+3 -3
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@@ -1454,9 +1454,9 @@
}
},
"node_modules/source-map-js": {
"version": "1.2.1",
"resolved": "https://registry.npmjs.org/source-map-js/-/source-map-js-1.2.1.tgz",
"integrity": "sha512-UXWMKhLOwVKb728IUtQPXxfYU+usdybtUrK/8uGE8CQMvrhOpwvzDBwj0QhSL7MQc7vIsISBG8VQ8+IDQxpfQA==",
"version": "1.2.2",
"resolved": "https://registry.npmjs.org/source-map-js/-/source-map-js-1.2.2.tgz",
"integrity": "sha512-KGj/8Y43x35aZVDtt+J4mK1hoLGHULMYfSkODJNQjNDC3oW1PqPoxMwo0pLUsWM/UEGzON/NxeHywEfNXNP3Vw==",
"license": "BSD-3-Clause",
"engines": {
"node": ">=0.10.0"