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Niels Lohmann
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* Clean up README, contribution guide, and repository metadata - REUSE.toml: fix the Hedley path and SPDX id (CC0-1.0), mark the docset icons as the public-domain JSON logo - CITATION.cff: v3.12.0 was released on 2025-04-11 - FILES.md: list all workflows, describe the Meson option defaults - README: ctest -LE, table of contents, typos, stale Android/MinGW advice, moved links, merge duplicate Thanks entries, list the analysis tools used in CI - CONTRIBUTING: iterative parser, json_literals.hpp is generated, links - .gitignore: backups and release outputs; .gitattributes: mark generated files - labeler: label other build systems and .github documentation - MODULE.bazel: add the module version Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Clean up CI, CMake, Makefile, and Bazel files - CMakeLists.txt: avoid VERSION_GREATER_EQUAL, which CMake < 3.7 lacks - ci.cmake: test JSON_DisableTupleReferenceConversion in ci_cmake_flags, remove unused variables and unreachable per-compiler targets, look up Clang tools consistently, forward CMAKE_CXX_FLAGS to ci_module_cpp20, format json_literals.hpp and remove backups in ci_test_amalgamation - BUILD.bazel: add json_literals.hpp to the single-header target - workflows: format json_literals.hpp before copying it, drop the obsolete natvis --version plumbing, name natvis and macro_builder in failure messages, drop the duplicate amalgamation job, install Valgrind only where needed, republish docs on version bumps, fix stale names - Makefile: complete .PHONY and help, check-amalgamation always restores the checked-in files, natvis uses its own venv, macro_builder_check installs astyle, clean removes the fuzzer binaries - remove tools/amalgamate/config_json_view.json (json_view.hpp is not on develop yet) Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Fix inaccuracies in the documentation - version history: json_base_class_t (3.11.3), JSON_HAS_CPP_11 (3.10.0), JSON_HAS_RANGES exclusions, define-type macros, ABI tags - releases: 3.12.0 raised the minimum CMake version - from_*: the (ptr, len) overloads are deleted, not removed, in 4.0.0 - contains/count/find: document the deleted integral overloads - add JSON_HAS_RANGE_VIEW_CONVERSION and list the JSON_HAS_* macros in the macro overview - mention BON8 and error_handler where binary formats are listed - broken links, outdated URLs, warning count, Hunter v0.26.12 - copy_markdown_source hook: expand snippets in the Markdown copies Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Pass /EHsc to the Windows C++20 module build ci_module_cpp20 now forwards CMAKE_CXX_FLAGS to the module build. The Windows workflow sets CMAKE_CXX_FLAGS, which replaces CMake's MSVC defaults including /EHsc, so <chrono> failed with C4530 under /WX. Signed-off-by: Niels Lohmann <mail@nlohmann.me> --------- Signed-off-by: Niels Lohmann <mail@nlohmann.me>
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JSON_HAS_RANGES
#define JSON_HAS_RANGES /* value */
This macro indicates whether the standard library has any support for ranges. Implies support for concepts.
Possible values are 1 when supported or 0 when unsupported.
Default definition
The default value is detected based on the preprocessor macro #!cpp __cpp_lib_ranges.
When the macro is not defined, the library will define it to its default value.
!!! info "Known compiler/stdlib exclusions"
Even when the feature-test macro `__cpp_lib_ranges` indicates ranges support is available, the library disables it on
the following incomplete or broken toolchains:
- **GCC 11.1.0** — disabled (the shipped `<ranges>` header has a syntax error; [issue #4440](https://github.com/nlohmann/json/issues/4440))
- **libstdc++ < 11** — disabled (incomplete C++20 ranges support; [issue #4440](https://github.com/nlohmann/json/issues/4440))
- **Clang < 16 with libstdc++** — disabled (incomplete ranges support; [issue #5161](https://github.com/nlohmann/json/issues/5161))
- **libc++ < 160000** — disabled (incomplete C++20 ranges support; [issue #4440](https://github.com/nlohmann/json/issues/4440))
- **nvcc (CUDA) 12.0.x and 12.1.x** — disabled (the `enable_borrowed_range` variable-template syntax triggers a parse error
under these two toolkit versions; fixed in CUDA 12.2; [issue #3907](https://github.com/nlohmann/json/issues/3907))
If `JSON_HAS_RANGES` is `0` despite `__cpp_lib_ranges` being defined, one of the exclusions above likely applies to your toolchain.
Examples
??? example
The code below forces the library to enable support for ranges:
```cpp
#define JSON_HAS_RANGES 1
#include <nlohmann/json.hpp>
...
```
See also
- JSON_HAS_CPP_11 / JSON_HAS_CPP_14 / JSON_HAS_CPP_17 / JSON_HAS_CPP_20 / JSON_HAS_CPP_23 / JSON_HAS_CPP_26 - set supported C++ standard
- JSON_HAS_RANGE_VIEW_CONVERSION - control construction from
std::rangesviews - JSON_HAS_STD_FORMAT - a similar feature-detection macro, for
std::format/std::formattersupport
Version history
- Added in version 3.11.0.
- Added the exclusions for libstdc++ < 11, Clang < 16 with libstdc++, libc++ < 16, and nvcc (CUDA) 12.0.x and 12.1.x in version 3.13.0. Before, only GCC 11.1.0 was excluded.