Release date: 2020-08-06
SHA-256: 7804b38146921d03374549c9e2a5e3acda097814c43caf2b96a0278e58df26e0 (json.hpp), 6bea5877b1541d353bd77bdfbdb2696333ae5ed8f9e8cc22df657192218cad91 (include.zip)

This release fixes two bugs in the features introduced in release 3.9.0. The lexer did not accept **consecutive comments**, and **`ordered_json`  lacked some functions** from `json`. All changes are backward-compatible.

:moneybag: Note you can **support this project** via [GitHub sponsors](https://github.com/sponsors/nlohmann) or [PayPal](http://paypal.me/nlohmann).

- The lexer did not accept input with two or more consecutive comments (e.g. `/* one */ /* two */ []`). #2330 #2332
- The newly introduced `ordered_json` container did not implement the complete interface of `basic_json` which broke existing code when `json` was replaced by `ordered_json`, in particular when trying to call `ordered_json::parse`. #2315 #2319 #2331

- Install pkg-config file to `CMAKE_CURRENT_BINARY_DIR` instead of `CMAKE_BINARY_DIR` #2318
- Make installation directory of pkg-config file depend on `CMAKE_INSTALL_LIBDIR`. #2314
- Fix `-Wimplicit-fallthrough` warning. #2333
- Fix name of Homebrew formula in documentation. #2326 #2327
- Fix typo in documentation. #2320

The following functions have been deprecated in earlier versions and will be removed in the next major version (i.e., 4.0.0):

- Function [`iterator_wrapper`](https://nlohmann.github.io/json/doxygen/classnlohmann_1_1basic__json_a0a8051760196ac813fd5eb3c8d5a2976.html#a0a8051760196ac813fd5eb3c8d5a2976) are deprecated. Please use the member function [`items()`](https://nlohmann.github.io/json/doxygen/classnlohmann_1_1basic__json_a5961446010dfc494e0c247b4e9026977.html#a5961446010dfc494e0c247b4e9026977) instead.
- Functions [`friend std::istream& operator<<(basic_json&, std::istream&)`](https://nlohmann.github.io/json/doxygen/classnlohmann_1_1basic__json_a60ca396028b8d9714c6e10efbf475af6.html#a60ca396028b8d9714c6e10efbf475af6) and [`friend std::ostream& operator>>(const basic_json&, std::ostream&)`](https://nlohmann.github.io/json/doxygen/classnlohmann_1_1basic__json_a34d6a60dd99e9f33b8273a1c8db5669b.html#a34d6a60dd99e9f33b8273a1c8db5669b) are deprecated. Please use [`friend std::istream&  operator>>(std::istream&, basic_json&)`](https://nlohmann.github.io/json/doxygen/classnlohmann_1_1basic__json_aaf363408931d76472ded14017e59c9e8.html#aaf363408931d76472ded14017e59c9e8) and [`friend operator<<(std::ostream&, const basic_json&)`](https://nlohmann.github.io/json/doxygen/classnlohmann_1_1basic__json_a5e34c5435e557d0bf666bd7311211405.html#a5e34c5435e557d0bf666bd7311211405) instead.
- Passing iterator pairs or pointer/length pairs to parsing functions (`basic_json::parse`, `basic_json::accept`, `basic_json::sax_parse`, `basic_json::from_cbor`, `basic_json::from_msgpack`, `basic_json::from_ubjson`, `basic_json::from_bson`) via initializer lists is deprecated. Instead, pass the elements individually without braces.

All 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.

Release date: 2020-07-27
SHA-256: d8089d52d285ef2c5368eb39ae665b39ea464206b1ca674a88a915c0245ff4f0 (json.hpp), 5b9b819aed31626aefe2eace23498cafafc1691890556cd36d2a8002f6905009 (include.zip)

JSON for Modern C++ 3.9.0 is a feature release that adds four long-awaited features, some requested five years ago.

- The parser functions have now an option to ignore `//` and `/* */` style **comments**. Though comments are not officially part of the JSON specification (see [here](https://github.com/nlohmann/json#comments-in-json) for a discussion), comment support was a frequently requested feature, and its implementation was much less effort than continuously explaining the lack of comment support.
- The second-most requested feature was a way to **preserve the insertion order of object keys**. Though this was possible via template specialization for a while, we now added a new type `nlohmann::ordered_json` as drop-in replacement for `nlohmann::json` for this.
- To circumvent unexpected behavior, **implicit conversions** can now be switched off with a CMake or preprocessor option.
- Last, but not least, a mapping between user-defined types and JSON can now be expressed using **convenience macros** by just listing the names of the member variables to read/write.

All changes are backward-compatible. See below the complete list of changes. See the [README](https://github.com/nlohmann/json/blob/develop/README.md) or the [documentation](https://nlohmann.github.io/json/) for more information.

:moneybag: Note you can **support this project** via [GitHub sponsors](https://github.com/sponsors/nlohmann) or [PayPal](http://paypal.me/nlohmann).

- Add optional support for [**comments in JSON**](https://github.com/nlohmann/json#comments-in-json): passing parameter `ignore_comments` to the `parse` function will treat `//` and `/* */` comments like whitespace. #294 #363 #376 #597 #1513 #2061 #2212
- Add type `nlohmann::ordered_json` to [**preserve insertion order of object keys**](https://github.com/nlohmann/json#order-of-object-keys). `ordered_json` is a specialization of `basic_json` and can be used wherever `json` is used. #106 #424 #543 #660 #727 #952 #1106 #1717 #1817 #2179 #2206 #2258
- Add CMake option `JSON_ImplicitConversions` and preprocessor symbol `JSON_USE_IMPLICIT_CONVERSIONS` to [**switch off implicit conversions**](https://github.com/nlohmann/json#implicit-conversions). Implicit conversions, though very practical, are also a source of subtle bugs or unexpected behavior and may be switched off by default in future versions. The new options allow to remove implicit conversions now. #958 #1559
- Add [**convenience macros** `NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE` and `NLOHMANN_DEFINE_TYPE_INTRUSIVE`](https://github.com/nlohmann/json#simplify-your-life-with-macros) to simplify serialization/deserialization code for user-defined types. #2175 #2225 #2233 #2267 #2280 #2287 #2306 #2313
- Add **high-precision number support for UBJSON**. Now, any JSON value can serialized to UBJSON, and exception `json.exception.out_of_range.407` will no longer occur for integers larger than 9223372036854775807 (`LLONG_MAX`). #2297 #2286
- Write **binary subtype as CBOR tag**. #2244
- Add option to **ignore CBOR tags** as alternative to treat them as invalid input. #2308 #2273 #1968

- Fix bug in CBOR parser where `allow_exceptions` was not respected. #2299 #2298
- Fix bug in CBOR parser where incomplete binary values or strings could crash the parser. #2293 #2294

- Make code compile with **Clang on Windows**. #2259 #1119
- Use 32-bit float encoding in MessagePack wherever this is possible without loss of precision. #2201 #2196
- Replace `std::hash<nlohmann::basic_json>` with a function that does not allocate memory. #2292 #2285 #2269

- Use [GitLab Discussions](https://github.com/nlohmann/json/discussions) for support and feature requests. Removed and adjusted issue templates accordingly.
- Allow CMake 3.13+ to override options when using `FetchContent`. #2222
- Add support for [pkg-config](https://github.com/nlohmann/json#pkg-config). #2253
- Add CMake option `JSON_TestDataDirectory` to select directory of previously downloaded test data for situations where Internet access is forbidden during testing. #2189 #2190
- Add [option to skip tests](https://github.com/nlohmann/json#execute-unit-tests) that assume the code is checked out via Git. #2189
- Add `JSON_ASSERT` macro to control behavior of assert calls. #2242
- Add CI step for [GitHub CodeQL analysis](https://github.com/nlohmann/json/actions?query=workflow%3A%22Code+scanning+-+action%22) (GitHub actions).
- Add CI step for Clang 9 and Clang 10 on Windows (GitHub actions). #2259
- Add CI step for Clang 10 CL with MSVC 2019 on Windows (GitHub actions). #2268
- Clean up GitHub actions CI. #2300
- Add CI step for Xcode 12 (Travis). #2262
- Add CI step for explicit conversions (Travis, AppVeyor).
- Remove `swap` specialization to support C++20. #2176
- Add missing check for `binary()` function in [SAX interface](https://github.com/nlohmann/json#sax-interface). #2282
- Add [test](https://github.com/nlohmann/json/tree/develop/test/cmake_target_include_directories/project) for CMake `target_include_directories`. #2279
- Add test to use library in multiple translation units. #2301
- Add more sections to new [project website](https://nlohmann.github.io/json/). #2312
- Fix warnings. #2304 #2305 #2303 #2274 #2224 #2211 #2203
- Cleanup maintainer Makefiles. #2264 #2274
- Improve documentation. #2232
- Fix inconsistency in int-to-string function. #2193

This release deprecates passing iterator pairs or pointer/length pairs to parsing functions (`basic_json::parse`, `basic_json::accept`, `basic_json::sax_parse`, `basic_json::from_cbor`, `basic_json::from_msgpack`, `basic_json::from_ubjson`, `basic_json::from_bson`) via initializer lists. Instead, pass the elements individually without braces.

The following functions have been deprecated in earlier versions and will be removed in the next major version (i.e., 4.0.0):

- Function [`iterator_wrapper`](https://nlohmann.github.io/json/doxygen/classnlohmann_1_1basic__json_a0a8051760196ac813fd5eb3c8d5a2976.html#a0a8051760196ac813fd5eb3c8d5a2976) are deprecated. Please use the member function [`items()`](https://nlohmann.github.io/json/doxygen/classnlohmann_1_1basic__json_a5961446010dfc494e0c247b4e9026977.html#a5961446010dfc494e0c247b4e9026977) instead.
- Functions [`friend std::istream& operator<<(basic_json&, std::istream&)`](https://nlohmann.github.io/json/doxygen/classnlohmann_1_1basic__json_a60ca396028b8d9714c6e10efbf475af6.html#a60ca396028b8d9714c6e10efbf475af6) and [`friend std::ostream& operator>>(const basic_json&, std::ostream&)`](https://nlohmann.github.io/json/doxygen/classnlohmann_1_1basic__json_a34d6a60dd99e9f33b8273a1c8db5669b.html#a34d6a60dd99e9f33b8273a1c8db5669b) are deprecated. Please use [`friend std::istream&  operator>>(std::istream&, basic_json&)`](https://nlohmann.github.io/json/doxygen/classnlohmann_1_1basic__json_aaf363408931d76472ded14017e59c9e8.html#aaf363408931d76472ded14017e59c9e8) and [`friend operator<<(std::ostream&, const basic_json&)`](https://nlohmann.github.io/json/doxygen/classnlohmann_1_1basic__json_a5e34c5435e557d0bf666bd7311211405.html#a5e34c5435e557d0bf666bd7311211405) instead.

All 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.

Release date: 2020-06-14
SHA-256: be7bbfbc7c62c35aa6f27dfbdd950384f247dd9f2281b5930bdaa3a6ab95eef7 (json.hpp), 8590fbcc2346a3eefc341935765dd57598022ada1081b425678f0da9a939a3c0 (include.zip)

It has been six months since the last release, and a lot of minor changes and bug fixes have accumulated. Nonetheless, JSON for Modern C++ 3.8.0 is a feature release.

- With **binary values** we greatly extend the support for binary formats such as CBOR, BSON, or MessagePack. By adding a new value type to the JSON class, binary values can be read and written, and even shared between different formats. See [the documentation](https://github.com/nlohmann/json#binary-formats-bson-cbor-messagepack-and-ubjson) for examples.

- Furthermore, we overworked the **input adapters**; that is, the way input is read by the parsers. Now any container is supported via the `LegacyInputIterator` concept. See [the documentation](https://github.com/nlohmann/json#custom-data-source) for examples. At the same time, we could improve the performance by 3-10%.

All changes are backward-compatible. See below the complete list of changes.

:moneybag: Note you can now **support this project** via [GitHub sponsors](https://github.com/sponsors/nlohmann) or [PayPal](http://paypal.me/nlohmann).

- The library now supports binary values for CBOR (byte arrays), BSON, and MessagePack (bin, ext, fixext). The values are parsed into a byte vector for further processing. #483 #757 #1129 #1509 #1662 #1668 #2064 #2069 #2071 #2082 #2099
- The input adapters have been generalized to read from any container including user-defined containers via `LegacyInputIterator`. The encoding of the input is implicitly derived from the size of the value type: UTF-8 (1 byte), UTF-16 (2 bytes), and UTF-32 (4 bytes) are supported. #1813 #2145 #2174 #2178
- CBOR now encodes floating-point numbers that can be represented by a `float` as `float` to save space in the serialization (32 bit va. 64 bit). #1719 #2044

- The functions to parse binary formats (`from_bson`, `from_cbor`, `from_msgpack`, and `from_ubjson`) now properly respect the `allow_exceptions=false` parameter. #1715 #2140
- The `contains` function for JSON Pointers now returns `false` in all cases a syntactically correct JSON Pointer refers to a non-existing value. Previously, an exception was raised if a JSON Pointer referred to an array, but did not consist of a number. #1942 #1982 #2019
- Fixed the JSON Pointer parser which accepted numbers with leading `+` as array index. #1990
- Fixed JSON Patch generation to properly use `/-` in the `add` operation for arrays. #1983 #2054
- Fixed compilation errors using GCC 10. #1912 #1920 #2034
- Fixed compilation errors using MSVC 2019. #1695 #1810 #1958 #2006 #2008 #2009
- Fixed a preprocessor check for some MSVC versions. #2112 #2137
- Fixed possible memory leak in `push_back`. #1971 #2025
- Removed broken overload of the `value()` function with `json::value_t type` parameter. #2086 #2104
- Removed values from arrays in case they are discarded by a parser callback function. Such values remained in the array with type `discarded` before. #1972 #2153

- The input adapters are now used via templates rather than inheriting from an abstract base class. This brings a 3-10% speedup for all parsers. #1457 #1950
- Test files are now downloaded from an [external repository](https://github.com/nlohmann/json_test_data) such that the code repository got much smaller and can be used as submodule more easily. #96 #482 #556 #567 #620 #732 #1066 #1184 #1185 #1235 #1497 #1572 #1790 #2081
- Made CMake's version config file architecture-independent. #1697 #1746

- Added links to [GitHub sponsors](https://github.com/sponsors/nlohmann) and listed named sponsors.
- Documented the integration of the library via CMake [FetchContent](https://cmake.org/cmake/help/v3.11/module/FetchContent.html) #2073 #2074
- Doozer CI was removed as it seems to exist no longer. #2080
- Added GitHub Actions workflows to build with Ubuntu, macOS, and Windows.
- Added GCC 10.1 to the continuous integration. #2136
- Fixed the Coveralls integration. #2100
- Fixed the error message for invalid surrogate pairs. #2076
- Fixed documentation. #1853 #1857 #1895 #1903 #1907 #1915 #1917 #1918 #1923 #1956 #1979 #1980 #2002 #2060 #2077 #2142 #2143 #2152
- Added test cases for NaN value in CBOR. #2043
- Documented curious behavior when using the library with glibc. #1924 #1933
- Fixed compiler warnings. #1939 #1911 #1967 #1969 #2049 #2051 #2053 #2113 #2116 #2144 #2177
- Updated Doctest to version 2.3.7. #2048 #2050
- Updated Hedley to version 13.
- Removed `std::is_pod` usage as it is deprecated in C++20. #1913 #2033 #2109
- Added [wsjcpp](https://wsjcpp.org) package manager. #2004
- Added [Build2](https://build2.org/) package manager. #1909
- Fixed compiler warning in test case. #1871
- Updated copyright year. #2010
- Updated CMake tests. #1844
- Removed a duplicated test. #2158
- Removed outdated Travis macOS images for Xcode 8.3, Xcode 9.0, Xcode 9.1, and Xcode 9.2. Added Xcode 11.2 image.
- Added [FOSSA](https://app.fossa.com/projects/git%2Bgithub.com%2Fnlohmann%2Fjson?ref=badge_shield) analysis.
- Header `<ciso646>` is deprecated in C++17 and not included if library is compiled with C++17. #2089 .#2115
- Updated the templates for bug fix reports, feature requests, and questions.
- Added fuzz tests for the all UBJSON modes. #2182
- Used [`HEDLEY_DEPRECATED_FOR`](https://nemequ.github.io/hedley/api-reference.html#HEDLEY_DEPRECATED_FOR) to indicate deprecated functions to have supporting compilers report which function to use instead.

This release deprecates passing iterator pairs or pointer/length pairs to parsing functions (`basic_json::parse`, `basic_json::accept`, `basic_json::sax_parse`, `basic_json::from_cbor`, `basic_json::from_msgpack`, `basic_json::from_ubjson`, `basic_json::from_bson`) via initializer lists. Instead, pass the elements individually without braces.

The following functions have been deprecated in earlier versions and will be removed in the next major version (i.e., 4.0.0):

- Function [`iterator_wrapper`](https://nlohmann.github.io/json/doxygen/classnlohmann_1_1basic__json_a0a8051760196ac813fd5eb3c8d5a2976.html#a0a8051760196ac813fd5eb3c8d5a2976) are deprecated. Please use the member function [`items()`](https://nlohmann.github.io/json/doxygen/classnlohmann_1_1basic__json_a5961446010dfc494e0c247b4e9026977.html#a5961446010dfc494e0c247b4e9026977) instead.
- Functions [`friend std::istream& operator<<(basic_json&, std::istream&)`](https://nlohmann.github.io/json/doxygen/classnlohmann_1_1basic__json_a60ca396028b8d9714c6e10efbf475af6.html#a60ca396028b8d9714c6e10efbf475af6) and [`friend std::ostream& operator>>(const basic_json&, std::ostream&)`](https://nlohmann.github.io/json/doxygen/classnlohmann_1_1basic__json_a34d6a60dd99e9f33b8273a1c8db5669b.html#a34d6a60dd99e9f33b8273a1c8db5669b) are deprecated. Please use [`friend std::istream&  operator>>(std::istream&, basic_json&)`](https://nlohmann.github.io/json/doxygen/classnlohmann_1_1basic__json_aaf363408931d76472ded14017e59c9e8.html#aaf363408931d76472ded14017e59c9e8) and [`friend operator<<(std::ostream&, const basic_json&)`](https://nlohmann.github.io/json/doxygen/classnlohmann_1_1basic__json_a5e34c5435e557d0bf666bd7311211405.html#a5e34c5435e557d0bf666bd7311211405) instead.

All 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.

Release date: 2019-11-10
SHA-256: 0a65fcbbe1b334d3f45c9498e5ee28c3f3b2428aea98557da4a3ff12f0f14ad6 (json.hpp), 67f69c9a93b7fa0612dc1b6273119d2c560317333581845f358aaa68bff8f087 (include.zip)

Project [bad_json_parsers](https://github.com/lovasoa/bad_json_parsers) tested how JSON parser libraries react on **deeply nested inputs**. It turns out that this library segfaulted at a certain nesting depth. This bug was fixed with this release. **Now the parsing is only bounded by the available memory.** All changes are backward-compatible.

* Fixed a bug that lead to stack overflow for deeply nested JSON values (objects, array) by changing the implementation of the destructor from a recursive to an iterative approach. #832, #1419, #1835

* Added WhiteStone Bolt. #1830

This release does not deprecate any functions. As an overview, the following functions have been deprecated in earlier versions and will be removed in the next major version (i.e., 4.0.0):

- Function [`iterator_wrapper`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_af1592a06bc63811886ade4f9d965045e.html#af1592a06bc63811886ade4f9d965045e) are deprecated. Please use the member function [`items()`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_afe3e137ace692efa08590d8df40f58dd.html#afe3e137ace692efa08590d8df40f58dd) instead.
- Functions [`friend std::istream& operator<<(basic_json&, std::istream&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_ab7285a92514fcdbe6de505ebaba92ea3.html#ab7285a92514fcdbe6de505ebaba92ea3) and [`friend std::ostream& operator>>(const basic_json&, std::ostream&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a9e06deabe69262c3ffc5533d32856983.html#a9e06deabe69262c3ffc5533d32856983) are deprecated. Please use [`friend std::istream&  operator>>(std::istream&, basic_json&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_aaf363408931d76472ded14017e59c9e8.html#aaf363408931d76472ded14017e59c9e8) and [`friend operator<<(std::ostream&, const basic_json&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a5e34c5435e557d0bf666bd7311211405.html#a5e34c5435e557d0bf666bd7311211405) instead.

Release date: 2019-11-17
SHA-256: 3b5d2b8f8282b80557091514d8ab97e27f9574336c804ee666fda673a9b59926 (json.hpp), 87b5884741427220d3a33df1363ae0e8b898099fbc59f1c451113f6732891014 (include.zip)

This release fixes a bug introduced in release 3.7.2 which could yield quadratic complexity in destructor calls. All changes are backward-compatible.

- Removed `reserve()` calls from the destructor which could lead to quadratic complexity. #1837 #1838

This release does not deprecate any functions. As an overview, the following functions have been deprecated in earlier versions and will be removed in the next major version (i.e., 4.0.0):

- Function [`iterator_wrapper`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_af1592a06bc63811886ade4f9d965045e.html#af1592a06bc63811886ade4f9d965045e) are deprecated. Please use the member function [`items()`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_afe3e137ace692efa08590d8df40f58dd.html#afe3e137ace692efa08590d8df40f58dd) instead.
- Functions [`friend std::istream& operator<<(basic_json&, std::istream&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_ab7285a92514fcdbe6de505ebaba92ea3.html#ab7285a92514fcdbe6de505ebaba92ea3) and [`friend std::ostream& operator>>(const basic_json&, std::ostream&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a9e06deabe69262c3ffc5533d32856983.html#a9e06deabe69262c3ffc5533d32856983) are deprecated. Please use [`friend std::istream&  operator>>(std::istream&, basic_json&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_aaf363408931d76472ded14017e59c9e8.html#aaf363408931d76472ded14017e59c9e8) and [`friend operator<<(std::ostream&, const basic_json&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a5e34c5435e557d0bf666bd7311211405.html#a5e34c5435e557d0bf666bd7311211405) instead.

Release date: 2019-07-28
SHA-256: a503214947952b69f0062f572cb74c17582a495767446347ce2e452963fc2ca4 (json.hpp), 541c34438fd54182e9cdc68dd20c898d766713ad6d901fb2c6e28ff1f1e7c10d (include.zip)

This release introduces a few convenience functions and performs a lot of house keeping (bug fixes and small improvements). All changes are backward-compatible.

- Add overload of the **[`contains`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_ab23b04802eb9da97dc3f664e54e09cb3.html#ab23b04802eb9da97dc3f664e54e09cb3) function** to check if a JSON pointer is valid without throwing exceptions, just like its [counterpart for object keys](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a9286acdc0578fc66e9346323e69fc0e3.html#a9286acdc0578fc66e9346323e69fc0e3). #1600
- Add a function **[`to_string`](http://nlohmann.github.io/json/namespacenlohmann_a6ce645a0b8717757e096a5b5773b7a16.html#a6ce645a0b8717757e096a5b5773b7a16)** to allow for generic conversion to strings. #916 #1585
- Add **return value for the [`emplace_back`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_abf29131f898b05aad2c01a9c80e7a002.html#abf29131f898b05aad2c01a9c80e7a002) function**, returning a reference to the added element just like C++17 is [introducing this](https://en.cppreference.com/w/cpp/container/vector/emplace_back) for `std::vector`. #1609
- Add info how to use the library with the **[pacman](https://wiki.archlinux.org/index.php/pacman) package manager** on MSYS2. #1670

- Fix an issue where typedefs with certain names yielded a compilation error. #1642 #1643
- Fix a conversion to `std::string_view` in the unit tests. #1634 #1639
- Fix MSVC Debug build. #1536 #1570 #1608
- Fix [`get_to`](https://nlohmann.github.io/json/classnlohmann_1_1basic__json_a65753c68f06639eda0d355f919564e01.html#a65753c68f06639eda0d355f919564e01) method to clear existing content before writing. #1511 #1555
- Fix a `-Wc++17-extensions` warning. `nodiscard` attributes are now only used with Clang when `-std=c++17` is used. #1535 #1551

- Switch from [Catch](https://github.com/philsquared/Catch) to **[doctest](https://github.com/onqtam/doctest)** for the unit tests which speeds up compilation and runtime of the 112,112,308 tests.
- Add an explicit section to the [README](https://github.com/nlohmann/json/blob/develop/README.md) about the **frequently addressed topics** [character encoding](https://github.com/nlohmann/json#character-encoding), [comments in JSON](https://github.com/nlohmann/json#comments-in-json), and the [order of object keys](https://github.com/nlohmann/json#order-of-object-keys).

- Use [`GNUInstallDirs`](https://cmake.org/cmake/help/v3.0/module/GNUInstallDirs.html) to set library install directories. #1673
- Fix links in the [README](https://github.com/nlohmann/json/blob/develop/README.md). #1620 #1621 #1622 #1623 #1625
- Mention [`json` type](http://nlohmann.github.io/json/namespacenlohmann_a2bfd99e845a2e5cd90aeaf1b1431f474.html#a2bfd99e845a2e5cd90aeaf1b1431f474) on the [documentation start page](http://nlohmann.github.io/json/index.html). #1616
- Complete documentation of [`value()` function](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_adcf8ca5079f5db993820bf50036bf45d.html#adcf8ca5079f5db993820bf50036bf45d) with respect to `type_error.302` exception. #1601
- Fix links in the documentation. #1598
- Add regression tests for MSVC. #1543 #1570
- Use **[CircleCI](http://circleci.com)** for [continuous integration](https://circleci.com/gh/nlohmann/json).
- Use **[Doozer](https://doozer.io)** for [continuous integration](https://doozer.io/nlohmann/json) on Linux (CentOS, Raspbian, Fedora)
- Add tests to check each CMake flag (`JSON_BuildTests`, `JSON_Install`, `JSON_MultipleHeaders`, `JSON_Sanitizer`, `JSON_Valgrind`, `JSON_NoExceptions`, `JSON_Coverage`).
- Use [Hedley](https://nemequ.github.io/hedley/) to avoid re-inventing several compiler-agnostic feature macros like `JSON_DEPRECATED`, `JSON_NODISCARD`, `JSON_LIKELY`, `JSON_UNLIKELY`, `JSON_HAS_CPP_14`, or `JSON_HAS_CPP_17`. Functions taking or returning pointers are annotated accordingly when a pointer will not be null.
- Build and run tests on [AppVeyor](https://ci.appveyor.com/project/nlohmann/json) in DEBUG and RELEASE mode.

This release does not deprecate any functions. As an overview, the following functions have been deprecated in earlier versions and will be removed in the next major version (i.e., 4.0.0):

- Function [`iterator_wrapper`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_af1592a06bc63811886ade4f9d965045e.html#af1592a06bc63811886ade4f9d965045e) are deprecated. Please use the member function [`items()`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_afe3e137ace692efa08590d8df40f58dd.html#afe3e137ace692efa08590d8df40f58dd) instead.
- Functions [`friend std::istream& operator<<(basic_json&, std::istream&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_ab7285a92514fcdbe6de505ebaba92ea3.html#ab7285a92514fcdbe6de505ebaba92ea3) and [`friend std::ostream& operator>>(const basic_json&, std::ostream&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a9e06deabe69262c3ffc5533d32856983.html#a9e06deabe69262c3ffc5533d32856983) are deprecated. Please use [`friend std::istream&  operator>>(std::istream&, basic_json&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_aaf363408931d76472ded14017e59c9e8.html#aaf363408931d76472ded14017e59c9e8) and [`friend operator<<(std::ostream&, const basic_json&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a5e34c5435e557d0bf666bd7311211405.html#a5e34c5435e557d0bf666bd7311211405) instead.

Release date: 2019-11-06
SHA-256: b5ba7228f3c22a882d379e93d08eab4349458ee16fbf45291347994eac7dc7ce (json.hpp), 77b9f54b34e7989e6f402afb516f7ff2830df551c3a36973085e2c7a6b1045fe (include.zip)

This release fixes several small bugs in the library. All changes are backward-compatible.

- Fixed a segmentation fault when serializing `std::int64_t` minimum value. #1708 #1722
- Fixed the [`contains()`](https://nlohmann.github.io/json/classnlohmann_1_1basic__json_ab23b04802eb9da97dc3f664e54e09cb3.html#ab23b04802eb9da97dc3f664e54e09cb3) function for JSON Pointers. #1727 #1741
- Fixed too lax SFINAE guard for conversion from `std::pair` and `std::tuple` to `json`. #1805 #1806 #1825 #1826
- Fixed some regressions detected by UBSAN. Updated CI to use Clang-Tidy 7.1.0. #1716 #1728
- Fixed integer truncation in `iteration_proxy`. #1797
- Updated [Hedley](https://github.com/nemequ/hedley) to v11 to [fix a E2512 error](https://github.com/nemequ/hedley/issues/28) in MSVC. #1799
- Fixed a compile error in enum deserialization of non non-default-constructible types. #1647 #1821
- Fixed the conversion from `json` to `std::valarray`.

- The [`items()`](https://nlohmann.github.io/json/classnlohmann_1_1basic__json_afe3e137ace692efa08590d8df40f58dd.html#afe3e137ace692efa08590d8df40f58dd) function can now be used with a custom string type. #1765
- Made [`json_pointer::back`](https://nlohmann.github.io/json/classnlohmann_1_1json__pointer_a213bc67c32a30c68ac6bf06f5195d482.html#a213bc67c32a30c68ac6bf06f5195d482) `const`. #1764 #1769
- Meson is part of the release archive. #1672 #1694
- Improved documentation on the Meson and Spack package manager. #1694 #1720

- Added GitHub Workflow with `ubuntu-latest`/GCC 7.4.0 as CI step.
- Added GCC 9 to Travis CI to compile with C++20 support. #1724
- Added MSVC 2019 to the AppVeyor CI. #1780
- Added badge to [fuzzing status](https://bugs.chromium.org/p/oss-fuzz/issues/list?sort=-opened&can=1&q=proj:json).
- Fixed some cppcheck warnings. #1760
- Fixed several typos in the documentation. #1720 #1767 #1803
- Added documentation on the `JSON_THROW_USER`, `JSON_TRY_USER`, and `JSON_CATCH_USER` macros to control user-defined exception handling.
- Used GitHub's [CODEOWNERS](https://github.com/nlohmann/json/blob/develop/.github/CODEOWNERS) and [SECURITY](https://github.com/nlohmann/json/blob/develop/.github/SECURITY.md) feature.
- Removed `GLOB` from CMake files. #1779
- Updated to [Doctest](https://github.com/onqtam/doctest) 2.3.5.

This release does not deprecate any functions. As an overview, the following functions have been deprecated in earlier versions and will be removed in the next major version (i.e., 4.0.0):

- Function [`iterator_wrapper`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_af1592a06bc63811886ade4f9d965045e.html#af1592a06bc63811886ade4f9d965045e) are deprecated. Please use the member function [`items()`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_afe3e137ace692efa08590d8df40f58dd.html#afe3e137ace692efa08590d8df40f58dd) instead.
- Functions [`friend std::istream& operator<<(basic_json&, std::istream&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_ab7285a92514fcdbe6de505ebaba92ea3.html#ab7285a92514fcdbe6de505ebaba92ea3) and [`friend std::ostream& operator>>(const basic_json&, std::ostream&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a9e06deabe69262c3ffc5533d32856983.html#a9e06deabe69262c3ffc5533d32856983) are deprecated. Please use [`friend std::istream&  operator>>(std::istream&, basic_json&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_aaf363408931d76472ded14017e59c9e8.html#aaf363408931d76472ded14017e59c9e8) and [`friend operator<<(std::ostream&, const basic_json&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a5e34c5435e557d0bf666bd7311211405.html#a5e34c5435e557d0bf666bd7311211405) instead.

Release date: 2019-03-20
SHA-256: ce9839370f28094c71107c405affb3b08c4a098154988014cbb0800b1c44a831 (json.hpp), 237c5e66e7f8186a02804ce9dbd5f69ce89fe7424ef84adf6142e973bd9532f4 (include.zip)

ℹ️ **This release introduced a regression. Please update to [version 3.6.1](https://github.com/nlohmann/json/releases/tag/v3.6.1)!**

This release adds some **convenience functions for JSON Pointers**, introduces a [`contains`](
http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a0a45fc740637123fdf05fef970f8be47.html#a0a45fc740637123fdf05fef970f8be47) function to check if a key is present in an object, and improves the **performance of integer serialization**. Furthermore, a lot of small bug fixes and improvements have been made. All changes are backward-compatible.

- Overworked the public interface for JSON Pointers. The creation of JSON Pointers is simplified with [`operator/`](
http://nlohmann.github.io/json/classnlohmann_1_1json__pointer_a90a11fe6c7f37b1746a3ff9cb24b0d53.html#a90a11fe6c7f37b1746a3ff9cb24b0d53) and [`operator/=`](http://nlohmann.github.io/json/classnlohmann_1_1json__pointer_a7395bd0af29ac23fd3f21543c935cdfa.html#a7395bd0af29ac23fd3f21543c935cdfa). JSON Pointers can be inspected with [`empty`](http://nlohmann.github.io/json/classnlohmann_1_1json__pointer_a649252bda4a2e75a0915b11a25d8bcc3.html#a649252bda4a2e75a0915b11a25d8bcc3), [`back`](http://nlohmann.github.io/json/classnlohmann_1_1json__pointer_a6bd5b554c10f15672135c216893eef31.html#a6bd5b554c10f15672135c216893eef31),  and [`parent_pointer`](http://nlohmann.github.io/json/classnlohmann_1_1json__pointer_afdaacce1edb7145e0434e014f0e8685a.html#afdaacce1edb7145e0434e014f0e8685a), and manipulated with [`push_back`](http://nlohmann.github.io/json/classnlohmann_1_1json__pointer_a697d12b5bd6205f8866691b166b7c7dc.html#a697d12b5bd6205f8866691b166b7c7dc) and [`pop_back`](http://nlohmann.github.io/json/classnlohmann_1_1json__pointer_a4b1ee4d511ca195bed896a3da47e264c.html#a4b1ee4d511ca195bed896a3da47e264c). #1434
- Added a boolean method [`contains`](
http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a0a45fc740637123fdf05fef970f8be47.html#a0a45fc740637123fdf05fef970f8be47) to check whether an element exists in a JSON object with a given key. Returns false when called on non-object types. #1471 #1474

- Fixed a compilation issues with libc 2.12. #1483 #1514
- Fixed endian conversion on PPC64. #1489
- Fixed library to compile with GCC 9. #1472 #1492
- Fixed a compilation issue with GCC 7 on CentOS. #1496
- Fixed an integer overflow. #1447
- Fixed buffer flushing in serializer. #1445 #1446

- The performance of dumping integers has been greatly improved. #1411
- Added CMake parameter `JSON_Install` to control whether the library should be installed (default: on). #1330
- Fixed a lot of compiler and linter warnings. #1400 #1435 #1502
- Reduced required CMake version from 3.8 to 3.1. #1409 #1428 #1441 #1498
- Added `nodiscard` attribute to `meta()`, `array()`, `object()`, `from_cbor`, `from_msgpack`, `from_ubjson`, `from_bson`, and `parse`. #1433

- Added missing headers. #1500
- Fixed typos and broken links in README. #1417 #1423 #1425 #1451 #1455 #1491
- Fixed documentation of parse function. #1473
- Suppressed warning that cannot be fixed inside the library. #1401 #1468
- Imroved package manager suppert:
	- Updated Buckaroo instructions. #1495
	- Improved Meson support. #1463
	- Added Conda package manager documentation. #1430
	- Added NuGet package manager documentation. #1132
- Continuous Integration
	- Removed unstable or deprecated Travis builders (Xcode 6.4 - 8.2) and added Xcode 10.1 builder.
	- Added Clang 7 to Travis CI.
	- Fixed AppVeyor x64 builds. #1374 #1414
- Updated thirdparty libraries:
	- Catch 1.12.0 -> 1.12.2
	- Google Benchmark 1.3.0 -> 1.4.1
	- Doxygen 1.8.15 -> 1.8.16

This release does not deprecate any functions. As an overview, the following functions have been deprecated in earlier versions and will be removed in the next major version (i.e., 4.0.0):

- Function [`iterator_wrapper`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_af1592a06bc63811886ade4f9d965045e.html#af1592a06bc63811886ade4f9d965045e) are deprecated. Please use the member function [`items()`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_afe3e137ace692efa08590d8df40f58dd.html#afe3e137ace692efa08590d8df40f58dd) instead.
- Functions [`friend std::istream& operator<<(basic_json&, std::istream&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_ab7285a92514fcdbe6de505ebaba92ea3.html#ab7285a92514fcdbe6de505ebaba92ea3) and [`friend std::ostream& operator>>(const basic_json&, std::ostream&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a9e06deabe69262c3ffc5533d32856983.html#a9e06deabe69262c3ffc5533d32856983) are deprecated. Please use [`friend std::istream&  operator>>(std::istream&, basic_json&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_aaf363408931d76472ded14017e59c9e8.html#aaf363408931d76472ded14017e59c9e8) and [`friend operator<<(std::ostream&, const basic_json&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a5e34c5435e557d0bf666bd7311211405.html#a5e34c5435e557d0bf666bd7311211405) instead.

Release date: 2019-03-20
SHA-256: d2eeb25d2e95bffeb08ebb7704cdffd2e8fca7113eba9a0b38d60a5c391ea09a (json.hpp), 69cc88207ce91347ea530b227ff0776db82dcb8de6704e1a3d74f4841bc651cf (include.zip)

This release **fixes a regression and a bug** introduced by the earlier 3.6.0 release. All changes are backward-compatible.

- Fixed regression of #590 which could lead to compilation errors with GCC 7 and GCC 8. #1530
- Fixed a compilation error when `<Windows.h>` was included. #1531

- Fixed a warning for missing field initializers. #1527

This release does not deprecate any functions. As an overview, the following functions have been deprecated in earlier versions and will be removed in the next major version (i.e., 4.0.0):

- Function [`iterator_wrapper`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_af1592a06bc63811886ade4f9d965045e.html#af1592a06bc63811886ade4f9d965045e) are deprecated. Please use the member function [`items()`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_afe3e137ace692efa08590d8df40f58dd.html#afe3e137ace692efa08590d8df40f58dd) instead.
- Functions [`friend std::istream& operator<<(basic_json&, std::istream&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_ab7285a92514fcdbe6de505ebaba92ea3.html#ab7285a92514fcdbe6de505ebaba92ea3) and [`friend std::ostream& operator>>(const basic_json&, std::ostream&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a9e06deabe69262c3ffc5533d32856983.html#a9e06deabe69262c3ffc5533d32856983) are deprecated. Please use [`friend std::istream&  operator>>(std::istream&, basic_json&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_aaf363408931d76472ded14017e59c9e8.html#aaf363408931d76472ded14017e59c9e8) and [`friend operator<<(std::ostream&, const basic_json&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a5e34c5435e557d0bf666bd7311211405.html#a5e34c5435e557d0bf666bd7311211405) instead.

Release date: 2018-10-05
SHA-256: f1327bb60c58757a3dd2b0c9c45d49503d571337681d950ec621f8374bcc14d4 (json.hpp), 9588d63557333aaa485e92221ec38014a85a6134e7486fe3441e0541a5a89576 (include.zip)

This release adds support for **GCC 4.8**. Furthermore, it adds a function [**`get_to`**](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a8a3db7d78f74232d3a6fb8f1abf69709.html#a8a3db7d78f74232d3a6fb8f1abf69709) to write a JSON value to a passed reference. Another topic of this release was the **CMake support** which has been overworked and documented.

Besides, a lot of bugs have been fixed and slight improvements have been made. All changes are backward-compatible.

- The library can now also built with **GCC 4.8**. Though this compiler does not fully support C++11, it can successfully compile and run the test suite. Note that bug [57824](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57824) in GCC 4.8 still forbids to use multiline raw strings in arguments to macros. #1257
- Added new function [**`get_to`**](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a8a3db7d78f74232d3a6fb8f1abf69709.html#a8a3db7d78f74232d3a6fb8f1abf69709) to write a JSON value to a passed reference. The destination type is automatically derived which allows more succinct code compared to the `get` function. #1227 #1231

- Fixed a bug in the CMake file that made `target_link_libraries` to not properly include `nlohmann_json`. #1243 #1245 #1260
- Fixed a warning in MSVC 2017 complaining about a constexpr if. #1204 #1268 #1272
- Fixed a bug that prevented compilation with ICPC. #755 #1222
- Improved the SFINAE correctness to fix a bug in the conversion operator. #1237 #1238
- Fixed a `-Wctor-dtor-privacy` warning. #1224
- Fixed a warning on a lambda in unevaluated context. #1225 #1230
- Fixed a bug introduced in version 3.2.0 where defining `JSON_CATCH_USER` led to duplicate macro definition of `JSON_INTERNAL_CATCH`. #1213 #1214
- Fixed a bug that prevented compilation with Clang 3.4.2 in RHEL 7. #1179 #1249

- Added [documentation on CMake integration](https://github.com/nlohmann/json#cmake) of the library. #1270
- Changed the CMake file to use `find_package(nlohmann_json)` without installing the library. #1202
- Improved error messages in case `operator[]` is used with the wrong combination (json.exception.type_error.305) of JSON container type and argument type. Example: "cannot use operator[] with a string argument". #1220 #1221
- Added a license and version information to the Meson build file. #1252
- Removed static assertions to indicated missing `to_json` or `from_json` functions as such assertions do not play well with SFINAE. These assertions also led to problems with GMock. #960 #1212 #1228
- The test suite now does not wait forever if run in a wrong directory and input files are not found. #1262
- The test suite does not show deprecation warnings for deprecated functions which frequently led to confusion. #1271

- GCC 4.8 and Xcode 10 were added to the [continuous integration suite](https://travis-ci.org/nlohmann/json) at Travis.
- Added [lgtm](https://lgtm.com/projects/g/nlohmann/json/context:cpp) checks to pull requests.
- Added tests for CMake integration. #1260

This release does not deprecate any functions. As an overview, the following functions have been deprecated in earlier versions and will be removed in the next major version (i.e., 4.0.0):

- Function [`iterator_wrapper`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_af1592a06bc63811886ade4f9d965045e.html#af1592a06bc63811886ade4f9d965045e) are deprecated. Please use the member function [`items()`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_afe3e137ace692efa08590d8df40f58dd.html#afe3e137ace692efa08590d8df40f58dd) instead.
- Functions [`friend std::istream& operator<<(basic_json&, std::istream&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_ab7285a92514fcdbe6de505ebaba92ea3.html#ab7285a92514fcdbe6de505ebaba92ea3) and [`friend std::ostream& operator>>(const basic_json&, std::ostream&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a9e06deabe69262c3ffc5533d32856983.html#a9e06deabe69262c3ffc5533d32856983) are deprecated. Please use [`friend std::istream&  operator>>(std::istream&, basic_json&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_aaf363408931d76472ded14017e59c9e8.html#aaf363408931d76472ded14017e59c9e8) and [`friend operator<<(std::ostream&, const basic_json&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a5e34c5435e557d0bf666bd7311211405.html#a5e34c5435e557d0bf666bd7311211405) instead.

Release date: 2018-10-30
SHA-256: 63da6d1f22b2a7bb9e4ff7d6b255cf691a161ff49532dcc45d398a53e295835f (json.hpp), bfec46fc0cee01c509cf064d2254517e7fa80d1e7647fea37cf81d97c5682bdc (include.zip)

This release introduces three new features:

- **BSON (Binary JSON)** is next to CBOR, MessagePack, and UBJSON the fourth binary (de)serialization format supported by the library.
- **Adjustable error handlers for invalid Unicode** allows to specify the behavior when invalid byte sequences are serialized.
- **Simplified enum/JSON mapping** with a macro in case the default mapping to integers is not desired.

Furthermore, some effort has been invested in improving the **parse error messages**. Besides, a few bugs have been fixed. All changes are backward-compatible.

- The library can read and write a subset of **[BSON](http://bsonspec.org/) (Binary JSON)**. All data types known from JSON are supported, whereas other types more tied to MongoDB such as timestamps, object ids, or binary data are currently not implemented. See [the README](https://github.com/nlohmann/json#binary-formats-bson-cbor-messagepack-and-ubjson) for examples. #1244 #1320
- The behavior when the library encounters an invalid Unicode sequence during serialization can now be controlled by defining one of three **Unicode error handlers**: (1) throw an exception (default behavior), (2) replace invalid sequences by the Unicode replacement character (U+FFFD), or (3) ignore/filter invalid sequences. See the [documentation of the `dump` function](https://nlohmann.github.io/json/classnlohmann_1_1basic__json_a50ec80b02d0f3f51130d4abb5d1cfdc5.html#a50ec80b02d0f3f51130d4abb5d1cfdc5) for examples. #1198 #1314
- To easily specify a user-defined **enum/JSON mapping**, a macro `NLOHMANN_JSON_SERIALIZE_ENUM` has been introduced. See the [README section](https://github.com/nlohmann/json#specializing-enum-conversion) for more information. #1208 #1323

- fixed truncation #1286 #1315
- fixed an issue with std::pair #1299 #1301
- fixed an issue with std::variant #1292 #1294
- fixed a bug in the JSON Pointer parser

- The **diagnosis messages for parse errors** have been improved: error messages now indicated line/column positions where possible (in addition to a byte count) and also the context in which the error occurred (e.g., "while parsing a JSON string"). Example: error `parse error at 2: syntax error - invalid string: control character must be escaped; last read: '<U+0009>'` is now reported as `parse error at line 1, column 2: syntax error while parsing value - invalid string: control character U+0009 (HT) must be escaped to \u0009 or \t; last read: '<U+0009>'`. #1280 #1288 #1303

- improved Meson documentation #1305
- fixed some more linter warnings #1280
- fixed Clang detection for third-party Google Benchmark library #1277

This release does not deprecate any functions. As an overview, the following functions have been deprecated in earlier versions and will be removed in the next major version (i.e., 4.0.0):

- Function [`iterator_wrapper`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_af1592a06bc63811886ade4f9d965045e.html#af1592a06bc63811886ade4f9d965045e) are deprecated. Please use the member function [`items()`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_afe3e137ace692efa08590d8df40f58dd.html#afe3e137ace692efa08590d8df40f58dd) instead.
- Functions [`friend std::istream& operator<<(basic_json&, std::istream&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_ab7285a92514fcdbe6de505ebaba92ea3.html#ab7285a92514fcdbe6de505ebaba92ea3) and [`friend std::ostream& operator>>(const basic_json&, std::ostream&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a9e06deabe69262c3ffc5533d32856983.html#a9e06deabe69262c3ffc5533d32856983) are deprecated. Please use [`friend std::istream&  operator>>(std::istream&, basic_json&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_aaf363408931d76472ded14017e59c9e8.html#aaf363408931d76472ded14017e59c9e8) and [`friend operator<<(std::ostream&, const basic_json&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a5e34c5435e557d0bf666bd7311211405.html#a5e34c5435e557d0bf666bd7311211405) instead.

Release date: 2018-12-22
SHA-256: 8a6dbf3bf01156f438d0ca7e78c2971bca50eec4ca6f0cf59adf3464c43bb9d5 (json.hpp), 3564da9c5b0cf2e032f97c69baedf10ddbc98030c337d0327a215ea72259ea21 (include.zip)

This release introduces the support for **structured bindings** and reading from **`FILE*`**. Besides, a few bugs have been fixed. All changes are backward-compatible.

- **Structured bindings** are now supported for JSON objects and arrays via the [`items()`](https://nlohmann.github.io/json/classnlohmann_1_1basic__json_afe3e137ace692efa08590d8df40f58dd.html#afe3e137ace692efa08590d8df40f58dd) member function, so finally this code is possible:
  ```cpp
  for (auto& [key, val] : j.items()) {
      std::cout << key << ':' << val << '\n';
  }
  ```
  #1388 #1391

- Added support for **reading from `FILE*`** to support situations in which streams are nit available or would require too much RAM. #1370 #1392

- The `eofbit` was not set for input streams when the end of a stream was reached while parsing. #1340 #1343
- Fixed a bug in the SAX parser for BSON arrays.

- Added support for Clang 5.0.1 (PS4 version). #1341 #1342

- Added a warning for implicit conversions to the documentation: It is not recommended to use implicit conversions when reading **from** a JSON value. Details about this recommendation can be found [here](https://www.github.com/nlohmann/json/issues/958).  #1363
- Fixed typos in the documentation. #1329 #1380 #1382
- Fixed a C4800 warning. #1364
- Fixed a `-Wshadow` warning #1346
- Wrapped `std::snprintf` calls to avoid error in MSVC. #1337
- Added code to allow installation via Meson. #1345

This release does not deprecate any functions. As an overview, the following functions have been deprecated in earlier versions and will be removed in the next major version (i.e., 4.0.0):

- Function [`iterator_wrapper`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_af1592a06bc63811886ade4f9d965045e.html#af1592a06bc63811886ade4f9d965045e) are deprecated. Please use the member function [`items()`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_afe3e137ace692efa08590d8df40f58dd.html#afe3e137ace692efa08590d8df40f58dd) instead.
- Functions [`friend std::istream& operator<<(basic_json&, std::istream&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_ab7285a92514fcdbe6de505ebaba92ea3.html#ab7285a92514fcdbe6de505ebaba92ea3) and [`friend std::ostream& operator>>(const basic_json&, std::ostream&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a9e06deabe69262c3ffc5533d32856983.html#a9e06deabe69262c3ffc5533d32856983) are deprecated. Please use [`friend std::istream&  operator>>(std::istream&, basic_json&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_aaf363408931d76472ded14017e59c9e8.html#aaf363408931d76472ded14017e59c9e8) and [`friend operator<<(std::ostream&, const basic_json&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a5e34c5435e557d0bf666bd7311211405.html#a5e34c5435e557d0bf666bd7311211405) instead.

Release date: 2018-08-20
SHA-256: ce6b5610a051ec6795fa11c33854abebb086f0fd67c311f5921c3c07f9531b44 (json.hpp), 35ee642558b90e2f9bc758995c4788c4b4d4dec54eef95fb8f38cb4d49c8fc7c (include.zip)

This release introduces a [**SAX interface**](https://nlohmann.github.io/json/structnlohmann_1_1json__sax.html) to the library. While this may be a very special feature used by only few people, it allowed to unify all functions that consumed input and created some kind of JSON value. Internally, now all existing functions like `parse`, `accept`, `from_cbor`, `from_msgpack`, and `from_ubjson` use the SAX interface with different event processors. This allowed to separate the input processing from the value generation. Furthermore, throwing an exception in case of a parse error is now optional and up to the event processor. Finally, the JSON parser is now non-recursive (meaning it does not use the call stack, but `std::vector<bool>` to track the hierarchy of structured values) which allows to process nested input more efficiently.

Furthermore, the library finally is able to parse from **wide string types**. This is the first step toward opening the library from UTF-8 to UTF-16 and UTF-32.

This release further fixes several bugs in the library. All changes are backward-compatible.

- added a parser with a **SAX interface** (#971, #1153)
- support to parse from **wide string types** `std::wstring`, `std::u16string`, and `std::u32string`; the input will be converted to UTF-8 (#1031)
- added support for **`std::string_view`** when using C++17 (#1028)
- allow to **roundtrip `std::map` and `std::unordered_map`** from JSON if key type is not convertible to string; in these cases, values are serialized to arrays of pairs (#1079, #1089, #1133, #1138)

- allow to create `nullptr_t` from JSON allowing to properly roundtrip `null` values (#1169)
- allow compare user-defined string types (#1130)
- better support for algorithms using iterators from `items()` (#1045, #1134)
- added parameter to avoid compilation error with MSVC 2015 debug builds (#1114)
- re-added accidentially skipped unit tests (#1176)
- fixed MSVC issue with `std::swap` (#1168)

- `key()` function for iterators returns a const reference rather than a string copy (#1098)
- binary formats CBOR, MessagePack, and UBJSON now supports `float` as type for floating-point numbers (#1021)

- changed issue templates
- improved continuous integration: added builders for Xcode 9.3 and 9.4, added builders for GCC 8 and Clang 6, added builder for MinGW, added builders for MSVC targeting x86
- required CMake version is now at least 3.8 (#1040)
- overworked CMake file wrt. packaging (#1048)
- added package managers: Spack (#1041) and CocoaPods (#1148)
- fixed Meson include directory (#1142)
- preprocessor macro `JSON_SKIP_UNSUPPORTED_COMPILER_CHECK` can skip the rejection of unsupported compilers - use at your own risk! (#1128)
- preprocessor macro `JSON_INTERNAL_CATCH`/`JSON_INTERNAL_CATCH_USER` allows to control the behavior of exception handling inside the library (#1187)
- added note on `char` to JSON conversion
- added note how to send security-related issue via encrypted email
- removed dependency to `std::stringstream` (#1117)
- added SPDX-License-Identifier
- added updated JSON Parsing Test Suite, described in [Parsing JSON is a Minefield 💣](http://seriot.ch/parsing_json.php)
- updated to Catch 1.12.0

This release does not deprecate any functions. As an overview, the following functions have been deprecated in earlier versions and will be removed in the next major version (i.e., 4.0.0):

- Function [`iterator_wrapper`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_af1592a06bc63811886ade4f9d965045e.html#af1592a06bc63811886ade4f9d965045e) are deprecated. Please use the member function [`items()`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_afe3e137ace692efa08590d8df40f58dd.html#afe3e137ace692efa08590d8df40f58dd) instead.
- Functions [`friend std::istream& operator<<(basic_json&, std::istream&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_ab7285a92514fcdbe6de505ebaba92ea3.html#ab7285a92514fcdbe6de505ebaba92ea3) and [`friend std::ostream& operator>>(const basic_json&, std::ostream&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a9e06deabe69262c3ffc5533d32856983.html#a9e06deabe69262c3ffc5533d32856983) are deprecated. Please use [`friend std::istream&  operator>>(std::istream&, basic_json&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_aaf363408931d76472ded14017e59c9e8.html#aaf363408931d76472ded14017e59c9e8) and [`friend operator<<(std::ostream&, const basic_json&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a5e34c5435e557d0bf666bd7311211405.html#a5e34c5435e557d0bf666bd7311211405) instead.

Release date: 2018-02-13
SHA-256: e14ce5e33d6a2daf748026bd4947f3d9686ca4cfd53d10c3da46a0a9aceb7f2e (json.hpp), fde771d4b9e4f222965c00758a2bdd627d04fb7b59e09b7f3d1965abdc848505 (include.zip)

This release fixes several bugs in the library. All changes are backward-compatible.

- Fixed parsing of **CBOR strings with indefinite length** (#961). Earlier versions of this library misinterpreted the CBOR standard and rejected input with the `0x7F` start byte.
- Fixed user-defined **conversion to vector type** (#924, #969). A wrong SFINAE check rejected code though a user-defined conversion was provided.
- Fixed documentation of the parser behavior for **objects with duplicate keys** (#963). The exact behavior is not specified by [RFC 8259](https://tools.ietf.org/html/rfc8259) and the library now also provides no guarantee which object key is stored.
- Added check to detect memory **overflow when parsing UBJSON containers** (#962). The optimized UBJSON format allowed for specifying an array with billions of `null` elements with a few bytes and the library did not check whether this size exceeded `max_size()`.

- [Code coverage](https://coveralls.io/github/nlohmann/json) is now calculated for the individual header files, allowing to find uncovered lines more quickly than by browsing through the single header version (#953, #957).
- A Makefile target `run_benchmarks` was added to quickly build and run the benchmark suite.
- The documentation was harmonized with respect to the header inclusion (#955). Now all examples and the README use `#include <nlohmann/json.hpp>` to allow for selecting `single_include` or `include` or whatever installation folder as include directory.
- Added note on how to use the library with the [cget](http://cget.readthedocs.io/en/latest/) package manager (#954).

This release does not deprecate any functions. As an overview, the following functions have been deprecated in earlier versions and will be removed in the next major version (i.e., 4.0.0):

- Function [`iterator_wrapper`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_af1592a06bc63811886ade4f9d965045e.html#af1592a06bc63811886ade4f9d965045e) are deprecated. Please use the member function [`items()`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_afe3e137ace692efa08590d8df40f58dd.html#afe3e137ace692efa08590d8df40f58dd) instead.
- Functions [`friend std::istream& operator<<(basic_json&, std::istream&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_ab7285a92514fcdbe6de505ebaba92ea3.html#ab7285a92514fcdbe6de505ebaba92ea3) and [`friend std::ostream& operator>>(const basic_json&, std::ostream&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a9e06deabe69262c3ffc5533d32856983.html#a9e06deabe69262c3ffc5533d32856983) are deprecated. Please use [`friend std::istream&  operator>>(std::istream&, basic_json&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_aaf363408931d76472ded14017e59c9e8.html#aaf363408931d76472ded14017e59c9e8) and [`friend operator<<(std::ostream&, const basic_json&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a5e34c5435e557d0bf666bd7311211405.html#a5e34c5435e557d0bf666bd7311211405) instead.

Release date: 2018-03-14
SHA-256: fbdfec4b4cf63b3b565d09f87e6c3c183bdd45c5be1864d3fcb338f6f02c1733 (json.hpp), 495362ee1b9d03d9526ba9ccf1b4a9c37691abe3a642ddbced13e5778c16660c (include.zip)

This release fixes several bugs in the library. All changes are backward-compatible.

- Fixed a **memory leak** occurring in the parser callback (#1001).
- Different **specializations of `basic_json`** (e.g., using different template arguments for strings or objects) can now be used in assignments (#972, #977, #986).
- Fixed a logical error in an iterator range check (#992).

- The parser and the serialization now support **user-defined string types** (#1006, #1009).

- **[Clang Analyzer](http://clang-analyzer.llvm.org)** is now used as additional static analyzer; see `make clang_analyze`.
- Overworked [README](https://github.com/nlohmann/json/blob/develop/README.md) by adding links to the [documentation](https://nlohmann.github.io/json/) (#981).

This release does not deprecate any functions. As an overview, the following functions have been deprecated in earlier versions and will be removed in the next major version (i.e., 4.0.0):

- Function [`iterator_wrapper`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_af1592a06bc63811886ade4f9d965045e.html#af1592a06bc63811886ade4f9d965045e) are deprecated. Please use the member function [`items()`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_afe3e137ace692efa08590d8df40f58dd.html#afe3e137ace692efa08590d8df40f58dd) instead.
- Functions [`friend std::istream& operator<<(basic_json&, std::istream&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_ab7285a92514fcdbe6de505ebaba92ea3.html#ab7285a92514fcdbe6de505ebaba92ea3) and [`friend std::ostream& operator>>(const basic_json&, std::ostream&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a9e06deabe69262c3ffc5533d32856983.html#a9e06deabe69262c3ffc5533d32856983) are deprecated. Please use [`friend std::istream&  operator>>(std::istream&, basic_json&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_aaf363408931d76472ded14017e59c9e8.html#aaf363408931d76472ded14017e59c9e8) and [`friend operator<<(std::ostream&, const basic_json&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a5e34c5435e557d0bf666bd7311211405.html#a5e34c5435e557d0bf666bd7311211405) instead.

Release date: 2017-12-17
SHA-256: 076d4a0cb890a3c3d389c68421a11c3d77c64bd788e85d50f1b77ed252f2a462

<img src="https://user-images.githubusercontent.com/159488/34072418-8f5ba396-e287-11e7-9de7-8bc7482ac23c.png" align="right">

After almost a year, here is finally a new release of JSON for Modern C++, and it is a major one! As we adhere to [semantic versioning](https://semver.org), this means the release includes some breaking changes, so please read the next section carefully before you update. But don't worry, we also added a few new features and put a lot of effort into fixing a lot of bugs and straighten out a few inconsistencies.

This section describes changes that change the public API of the library and may require changes in code using a previous version of the library. In section "Moving from 2.x.x to 3.0.0" at the end of the release notes, we describe in detail how existing code needs to be changed.

- The library now uses [**user-defined exceptions**](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a9a0aced019cb1d65bb49703406c84970.html#a9a0aced019cb1d65bb49703406c84970) instead of re-using those defined in `<stdexcept>` (#244). This not only allows to add more information to the exceptions (every exception now has an identifier, and parse errors contain the position of the error), but also to easily catch all library exceptions with a single `catch(json::exception)`.
- When strings with a different encoding as UTF-8 were stored in JSON values, their serialization could not be parsed by the library itself, as only UTF-8 is supported. To enforce this library limitation and improve consistency, **non-UTF-8 encoded strings now yield a `json::type_error` exception during serialization** (#838). The check for valid UTF-8 is realized with code from [Björn Hoehrmann](http://bjoern.hoehrmann.de/).
- **NaN and infinity values can now be stored inside the JSON value** without throwing an exception. They are, however, still serialized as `null` (#388).
- The library's iterator tag was changed from RandomAccessIterator to **[BidirectionalIterator](http://en.cppreference.com/w/cpp/concept/BidirectionalIterator)** (#593). Supporting RandomAccessIterator was incorrect as it assumed an ordering of values in a JSON objects which are unordered by definition.
- The library does not include the standard headers `<iostream>`, `<ctype>`, and `<stdexcept>` any more. You may need to add these headers to code relying on them.
- Removed constructor `explicit basic_json(std::istream& i, const parser_callback_t cb = nullptr)` which was deprecated in version 2.0.0 (#480).

To unify the interfaces and to improve similarity with the STL, the following functions are now deprecated and will be removed in the next major version (i.e., 4.0.0):

- [`friend std::istream& operator<<(basic_json&, std::istream&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_ab7285a92514fcdbe6de505ebaba92ea3.html#ab7285a92514fcdbe6de505ebaba92ea3)
- [`friend std::ostream& operator>>(const basic_json&, std::ostream&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a9e06deabe69262c3ffc5533d32856983.html#a9e06deabe69262c3ffc5533d32856983)

Please use [`friend std::istream&  operator>>(std::istream&, basic_json&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_aaf363408931d76472ded14017e59c9e8.html#aaf363408931d76472ded14017e59c9e8) and [`friend operator<<(std::ostream&, const basic_json&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a5e34c5435e557d0bf666bd7311211405.html#a5e34c5435e557d0bf666bd7311211405) instead.

With all this breaking and deprecation out of the way, let's talk about features!

- We improved the **diagnostic information for syntax errors** (#301). Now, an exception [`json::parse_error`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_af1efc2468e6022be6e35fc2944cabe4d.html#af1efc2468e6022be6e35fc2944cabe4d) is thrown which contains a detailed message on the error, but also a member `byte` to indicate the byte offset in the input where the error occurred.
- We added a **non-throwing syntax check** (#458): The new `accept` function returns a Boolean indicating whether the input is proper JSON. We also added a Boolean parameter `allow_exceptions` to the existing [`parse`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_aa9676414f2e36383c4b181fe856aa3c0.html#aa9676414f2e36383c4b181fe856aa3c0) functions to return a `discarded` value in case a syntax error occurs instead of throwing an exception.
- An [`update`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a1cfa9ae5e7c2434cab4cfe69bffffe11.html#a1cfa9ae5e7c2434cab4cfe69bffffe11) function was added to **merge two JSON objects** (#428). In case you are wondering: the name was inspired by [Python](https://docs.python.org/2/library/stdtypes.html#dict.update).
- The [`insert`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a1b0a4e60d56f1fe80501ed941e122892.html#a1b0a4e60d56f1fe80501ed941e122892) function now also supports an iterator range to add elements to an object.
- The binary exchange formats **CBOR and MessagePack can now be parsed from input streams and written to output streams** (#477).
- Input streams are now only read until the end of a JSON value instead of the end of the input (#367).
- The serialization function [`dump`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a5adea76fedba9898d404fef8598aa663.html#a5adea76fedba9898d404fef8598aa663) now has two optional parameters `ensure_ascii` to **escape all non-ASCII characters** with `\uxxxx` and an `indent_char` parameter to choose whether to **indent with spaces or tabs** (#654).
- Added **built-in type support** for C arrays (#502), `std::pair` and `std::tuple` (#563, #614), `enum` and `enum class` (#545), `std::vector<bool>` (#494). Fixed support for `std::valarray` (#702), `std::array` (#553), and `std::map<std::string, std::string>` (#600, #607).

Furthermore, there have been a lot of changes under the hood:

- Replaced the [re2c](http://re2c.org) generated scanner by a self-coded version which allows for a better modularization of the parser and better diagnostics. To test the new scanner, we added millions (8,860,608 to be exact) of unit tests to check all valid and invalid byte sequences of the Unicode standard.
- Google's OSS-Fuzz is still constantly fuzz-testing the library and found several issues that were fixed in this release (#497, #504, #514, #516, #518, #519, #575).
- We now also ignore UTF-8 byte order marks when parsing from an iterator range (#602).
- Values can be now moved from initializer lists (#663).
- Updated to [Catch](https://github.com/catchorg/Catch2) 1.9.7. Unfortunately, Catch2 currently has some performance issues.
- The non-exceptional paths of the library are now annotated with `__builtin_expect` to optimize branch prediction as long as no error occurs.
- MSVC now produces a stack trace in MSVC if a `from_json` or `to_json` function was not found for a user-defined type. We also added a debug visualizer [`nlohmann_json.natvis`](https://github.com/nlohmann/json/blob/develop/nlohmann_json.natvis) for better debugging in MSVC (#844).
- Overworked the documentation and added even more examples.
- The build workflow now relies on CMake and CTest. Special flags can be chosen with CMake, including coverage (`JSON_Coverage`), compilation without exceptions (`JSON_NoExceptions`), LLVM sanitizers (`JSON_Sanitizer`), or execution with Valgrind (`JSON_Valgrind`).
- Added support for package managers Meson (#576), Conan (#566), Hunter (#671, #829), and vcpkg (#753).
- Added CI builders: Xcode 8.3, 9.0, 9.1, and 9.2; GCC 7.2; Clang 3.8, 3.9, 4.0, and 5.0; Visual Studio 2017. The library is further built with C++17 settings on the latest Clang, GCC, and MSVC version to quickly detect new issues.

There are five different exceptions inheriting from [`json::exception`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a9a0aced019cb1d65bb49703406c84970.html#a9a0aced019cb1d65bb49703406c84970):

- [`json::parse_error`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_af1efc2468e6022be6e35fc2944cabe4d.html#af1efc2468e6022be6e35fc2944cabe4d) for syntax errors (including the binary formats),
- [`json::invalid_iterator`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_ac13d32f7cbd02d616e71d8dc30dadcbf.html#ac13d32f7cbd02d616e71d8dc30dadcbf) for errors related to iterators,
- [`json::type_error`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a4010e8e268fefd86da773c10318f2902.html#a4010e8e268fefd86da773c10318f2902) for errors where functions were called with the wrong JSON type,
- [`json::out_of_range`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a28f7c2f087274a0012eb7a2333ee1580.html#a28f7c2f087274a0012eb7a2333ee1580) for range errors, and
- [`json::other_error`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a3333a5a8714912adda33a35b369f7b3d.html#a3333a5a8714912adda33a35b369f7b3d) for miscellaneous errors.

To support these exception, the `try`/`catch` blocks of your code need to be adjusted:

| new exception | previous exception |
|:--|:--|
| parse_error.101 | invalid_argument |
| parse_error.102 | invalid_argument |
| parse_error.103 | invalid_argument |
| parse_error.104 | invalid_argument |
| parse_error.105 | invalid_argument |
| parse_error.106 | domain_error |
| parse_error.107 | domain_error |
| parse_error.108 | domain_error |
| parse_error.109 | invalid_argument |
| parse_error.110 | out_of_range |
| parse_error.111 | invalid_argument |
| parse_error.112 | invalid_argument |
| invalid_iterator.201 | domain_error |
| invalid_iterator.202 | domain_error |
| invalid_iterator.203 | domain_error |
| invalid_iterator.204 | out_of_range |
| invalid_iterator.205 | out_of_range |
| invalid_iterator.206 | domain_error |
| invalid_iterator.207 | domain_error |
| invalid_iterator.208 | domain_error |
| invalid_iterator.209 | domain_error |
| invalid_iterator.210 | domain_error |
| invalid_iterator.211 | domain_error |
| invalid_iterator.212 | domain_error |
| invalid_iterator.213 | domain_error |
| invalid_iterator.214 | out_of_range |
| type_error.301 | domain_error |
| type_error.302 | domain_error |
| type_error.303 | domain_error |
| type_error.304 | domain_error |
| type_error.305 | domain_error |
| type_error.306 | domain_error |
| type_error.307 | domain_error |
| type_error.308 | domain_error |
| type_error.309 | domain_error |
| type_error.310 | domain_error |
| type_error.311 | domain_error |
| type_error.313 | domain_error |
| type_error.314 | domain_error |
| type_error.315 | domain_error |
| out_of_range.401 | out_of_range |
| out_of_range.402 | out_of_range |
| out_of_range.403 | out_of_range |
| out_of_range.404 | out_of_range |
| out_of_range.405 | domain_error |
| other_error.501 | domain_error |

- If an overflow occurs during parsing a number from a JSON text, an exception [`json::out_of_range`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a28f7c2f087274a0012eb7a2333ee1580.html#a28f7c2f087274a0012eb7a2333ee1580) is thrown so that the overflow is detected early and roundtripping is guaranteed.

- NaN and INF floating-point values can be stored in a JSON value and are not replaced by null. That is, the basic_json class behaves like `double` in this regard (no exception occurs). However, NaN and INF are serialized to `null`.

Function `explicit basic_json(std::istream& i, const parser_callback_t cb = nullptr)` should be replaced by the `parse` function: Let `ss` be a stream and `cb` be a parse callback function.

Old code:

```cpp
json j(ss, cb);
```

New code:

```cpp
json j = json::parse(ss, cb);
```

If no callback function is used, also the following code works:

```cpp
json j;
j << ss;
```

or

```cpp
json j;
ss >> j;
```

Release date: 2017-12-29
SHA-256: c9b3591f1bb94e723a0cd7be861733a3a555b234ef132be1e9027a0364118c4c

This release fixes small issues in the implementation of **JSON Pointer** and **JSON Patch**. All changes are backward-compatible.

- :bug: The **"copy" operation of JSON Patch** ([RFC 6902](https://tools.ietf.org/html/rfc6902)) requests that it is an error if the target path points into a non-existing array or object (see #894 for a detailed description). This release fixes the implementation to detect such invalid target paths and throw an exception.
- :bug: An **array index in a JSON Pointer** ([RFC 6901](https://tools.ietf.org/html/rfc6901)) must be an integer. This release fixes the implementation to throw an exception in case invalid array indices such as `10e2` are used.
- :white_check_mark: Added the [JSON Patch tests](https://github.com/json-patch/json-patch-tests) from Byron Ruth and Mike McCabe.
- :memo: Fixed the documentation of the [`at(ptr)` function with JSON Pointers](https://nlohmann.github.io/json/classnlohmann_1_1basic__json_a8ab61397c10f18b305520da7073b2b45.html#a8ab61397c10f18b305520da7073b2b45) to list all possible exceptions (see #888).
- :memo: Updated the [container overview documentation](https://nlohmann.github.io/json/) (see #883).
- :wrench: The CMake files now respect the [`BUILD_TESTING`](https://cmake.org/cmake/help/latest/module/CTest.html?highlight=build_testing) option (see #846, #885)
- :rotating_light: Fixed some compiler warnings (see #858, #882).

:fire: To unify the interfaces and to improve similarity with the STL, the following functions are deprecated since version 3.0.0 and will be removed in the next major version (i.e., 4.0.0):

- [`friend std::istream& operator<<(basic_json&, std::istream&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_ab7285a92514fcdbe6de505ebaba92ea3.html#ab7285a92514fcdbe6de505ebaba92ea3)
- [`friend std::ostream& operator>>(const basic_json&, std::ostream&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a9e06deabe69262c3ffc5533d32856983.html#a9e06deabe69262c3ffc5533d32856983)

Please use [`friend std::istream&  operator>>(std::istream&, basic_json&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_aaf363408931d76472ded14017e59c9e8.html#aaf363408931d76472ded14017e59c9e8) and [`friend operator<<(std::ostream&, const basic_json&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a5e34c5435e557d0bf666bd7311211405.html#a5e34c5435e557d0bf666bd7311211405) instead.

Release date: 2018-02-01
SHA-256: d40f614d10a6e4e4e80dca9463da905285f20e93116c36d97d4dc1aa63d10ba4 (json.hpp), 2b7234fca394d1e27b7e017117ed80b7518fafbb4f4c13a7c069624f6f924673 (include.zip)

This release adds support for the [**UBJSON**](http://ubjson.org) format and [**JSON Merge Patch**](https://tools.ietf.org/html/rfc7386). It also contains some minor changes and bug fixes. All changes are backward-compatible.

- The library now supports [**UBJSON**](http://ubjson.org) (Universal Binary JSON Specification) as binary format to read and write JSON values space-efficiently. See the [documentation overview](https://github.com/nlohmann/json/blob/develop/doc/binary_formats.md) for a comparison of the different formats CBOR, MessagePack, and UBJSON.
- [**JSON Merge Patch**](https://tools.ietf.org/html/rfc7386) (RFC 7386) offers an intuitive means to describe patches between JSON values (#876, #877). See the documentation of [`merge_patch`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a0ec0cd19cce42ae6071f3cc6870ea295.html#a0ec0cd19cce42ae6071f3cc6870ea295) for more information.

- The library now uses the **Grisu2 algorithm** for printing floating-point numbers (based on the reference implementation by Florian Loitsch) which produces a short representation which is guaranteed to round-trip (#360, #935, #936).
- The **UTF-8 handling** was further simplified by using the decoder of Björn Hoehrmann in more scenarios.

- Though the library is released as a single header, its development got more and more complicated. With this release, the header is **split into several files** and the single-header file `json.hpp` can be generated from these development sources. In the repository, folder `include` contains the development sources and `single_include` contains the single `json.hpp` header (#700, #906, #907, #910, #911, #915, #920, #924, #925, #928, #944).
- The split further allowed for a **forward declaration header** `include/nlohmann/json_fwd.hpp` to speed up compilation times (#314).

- [Google Benchmark](https://github.com/google/benchmark) is now used for micro benchmarks (see `benchmarks` folder, #921).
- The serialization (JSON and binary formats) now properly work with the libraries string template parameter, allowing for optimized string implementations to be used in constraint environments such as embedded software (#941, #950).
- The exceptional behavior can now be overridden by defining macros `JSON_THROW_USER`, `JSON_TRY_USER`, and `JSON_CATCH_USER`, defining the behavior of `throw`, `try` and `catch`, respectively. This allows to switch off C++'s exception mechanism yet still execute user-defined code in case an error condition occurs (#938).
- To facilitate the interplay with [flex](https://github.com/westes/flex) and [Bison](https://www.gnu.org/software/bison/), the library does not use the variable name `yytext` any more as it could clash with macro definitions (#933).
- The library now defines `NLOHMANN_JSON_VERSION_MAJOR`, `NLOHMANN_JSON_VERSION_MINOR`, and `NLOHMANN_JSON_VERSION_PATCH` to allow for conditional compilation based on the included library version (#943, #948).
- A compilation error with ICC has been fixed (#947).
- Typos and links in the documentation have been fixed (#900, #930).
- A compiler error related to incomplete types has been fixed (#919).
- The tests form the [UTF-8 decoder stress test](http://www.cl.cam.ac.uk/~mgk25/ucs/examples/UTF-8-test.txt) have been added to the test suite.

- Function [`iterator_wrapper`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_af1592a06bc63811886ade4f9d965045e.html#af1592a06bc63811886ade4f9d965045e) has been deprecated (#874). Since its introduction, the name was up for discussion, as it was too technical. We now introduced the member function [`items()`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_afe3e137ace692efa08590d8df40f58dd.html#afe3e137ace692efa08590d8df40f58dd) with the same semantics. `iterator_wrapper` will be removed in the next major version (i.e., 4.0.0).

Furthermore, the following functions are deprecated since version 3.0.0 and will be removed in the next major version (i.e., 4.0.0):

- [`friend std::istream& operator<<(basic_json&, std::istream&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_ab7285a92514fcdbe6de505ebaba92ea3.html#ab7285a92514fcdbe6de505ebaba92ea3)
- [`friend std::ostream& operator>>(const basic_json&, std::ostream&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a9e06deabe69262c3ffc5533d32856983.html#a9e06deabe69262c3ffc5533d32856983)

Please use [`friend std::istream&  operator>>(std::istream&, basic_json&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_aaf363408931d76472ded14017e59c9e8.html#aaf363408931d76472ded14017e59c9e8) and [`friend operator<<(std::ostream&, const basic_json&)`](http://nlohmann.github.io/json/classnlohmann_1_1basic__json_a5e34c5435e557d0bf666bd7311211405.html#a5e34c5435e557d0bf666bd7311211405) instead.

- Release date: 2017-01-28
- SHA-256: a571dee92515b685784fd527e38405cf3f5e13e96edbfe3f03d6df2e363a767b

This release introduces a means to convert from/to user-defined types. The release is backwards compatible.

![conversion](https://cloud.githubusercontent.com/assets/159488/22399173/aebe8f7a-e597-11e6-930f-7494ee615827.png)

- :sparkles: The library now offers an elegant way to **convert from and to arbitrary value types**. All you need to do is to implement two functions: `to_json` and `from_json`. Then, a conversion is as simple as putting a `=` between variables. See the [README](https://github.com/nlohmann/json#arbitrary-types-conversions) for more information and examples.
- :sparkles: **Exceptions can now be switched off.** This can be done by defining the preprocessor symbol `JSON_NOEXCEPTION` or by passing `-fno-exceptions` to your compiler. In case the code would usually thrown an exception, `abort()` is now called.
- :sparkles: **Information on the library** can be queried with the new (static) function `meta()` which returns a JSON object with information on the version, compiler, and platform. See the [documentation]() for an example.
- :bug: A bug in the CBOR parser was fixed which led to a buffer overflow.
- :sparkles: The function [`type_name()`]() is now public. It allows to query the type of a JSON value as string.
- :white_check_mark: Added the [Big List of Naughty Strings](https://github.com/minimaxir/big-list-of-naughty-strings) as test case.
- :arrow_up: Updated to [Catch v1.6.0](https://github.com/philsquared/Catch/releases/tag/v1.6.0).
- :memo: Some typos in the documentation have been fixed.

Release date: 2017-02-25
SHA-256: faa2321beb1aa7416d035e7417fcfa59692ac3d8c202728f9bcc302e2d558f57

This release **fixes a locale-related bug in the parser**. To do so, the whole number handling (lexer, parser, and also the serialization) have been overworked. Furthermore, a lot of small changes added up that were added to this release. All changes are backward-compatible.

- :bug: Locales that have a different character than `.` as decimal separator (e.g., the Norwegian locale `nb_NO.UTF-8`) led to truncated number parsing or parse errors. The library now has been fixed to work with **any locale**. Note that `.` is still the only valid decimal separator for JSON input.
- :bug: Numbers like `1.0` were correctly parsed as floating-point number, but serialized as integer (`1`). Now, **floating-point numbers correctly round trip**.
- :bug: Parsing incorrect JSON numbers with leading 0 (`0123`) could yield a [buffer overflow](https://github.com/nlohmann/json/issues/452). This is fixed now by detecting such errors directly by the lexer.
- :bug: Constructing a JSON value from a pointer was incorrectly interpreted as a Boolean; such code will now yield a compiler error.
- :bug: Comparing a JSON number with `0` led to a comparison with `null`. This is fixed now.
- :bug: All throw calls are now wrapped in macros.
- :lock: Starting during the preparation of this release (since 8 February 2017), commits and released files are **cryptographically signed** with [this GPG key](https://keybase.io/nlohmann/pgp_keys.asc?fingerprint=797167ae41c0a6d9232e48457f3cea63ae251b69). Previous releases have also been signed.
- :sparkles: The parser for MessagePack and CBOR now supports an optional start index parameter to define a byte offset for the parser.
- :rotating_light: Some more warnings have been fixed. With Clang, the code compiles **without warnings** with `-Weverything` (well, it needs `-Wno-documentation-unknown-command` and `-Wno-deprecated-declarations`, but you get the point).
- :hammer: The code can be compiled easier with many Android NDKs by avoiding macros like `UINT8_MAX` which previously required defining a preprocessor macro for compilation.
- :zap: The unit tests now compile two times faster.
- :heavy_plus_sign: [Cotire](https://github.com/sakra/cotire) is used to speed up the build.
- :pencil2: Fixed a lot of typos in the documentation.
- :memo: Added a section to the README file that lists all used [third-party code/tools](https://github.com/nlohmann/json#used-third-party-tools).
- :memo: Added a note on constructing a string value vs. parsing.
- :white_check_mark: The test suite now contains 11202597 unit tests.
- :memo: Improved the [Doxygen documentation](https://nlohmann.github.io/json/) by shortening the template parameters of class `basic_json`.
- :construction_worker: Removed Doozer.
- :construction_worker: Added Codacity.
- :arrow_up: Upgraded Catch to version 1.7.2.