json/docs/mkdocs/docs/api/macros/index.md

Macros

Some aspects of the library can be configured by defining preprocessor macros before including the json.hpp header. See also the macro overview page.

Runtime assertions

• JSON_ASSERT(x) - control behavior of runtime assertions

Exceptions

• JSON_CATCH_USER(exception)
  JSON_THROW_USER(exception)
  JSON_TRY_USER - control exceptions
• JSON_DIAGNOSTICS - control extended diagnostics
• JSON_NOEXCEPTION - switch off exceptions

Language support

• JSON_HAS_CPP_11
  JSON_HAS_CPP_14
  JSON_HAS_CPP_17
  JSON_HAS_CPP_20 - set supported C++ standard
• JSON_HAS_FILESYSTEM
  JSON_HAS_EXPERIMENTAL_FILESYSTEM - control std::filesystem support
• JSON_HAS_RANGES - control std::ranges support
• JSON_HAS_THREE_WAY_COMPARISON - control 3-way comparison support
• JSON_NO_IO - switch off functions relying on certain C++ I/O headers
• JSON_SKIP_UNSUPPORTED_COMPILER_CHECK - do not warn about unsupported compilers

Library version

• JSON_SKIP_LIBRARY_VERSION_CHECK - skip library version check
• NLOHMANN_JSON_VERSION_MAJOR
  NLOHMANN_JSON_VERSION_MINOR
  NLOHMANN_JSON_VERSION_PATCH - library version information

Type conversions

• JSON_DISABLE_ENUM_SERIALIZATION - switch off default serialization/deserialization functions for enums
• JSON_USE_IMPLICIT_CONVERSIONS - control implicit conversions

Comparison behavior

• JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON - control comparison of discarded values

Serialization/deserialization macros

• NLOHMANN_DEFINE_TYPE_INTRUSIVE(type, member...)
  NLOHMANN_DEFINE_TYPE_INTRUSIVE_WITH_DEFAULT(type, member...) - serialization/deserialization of types with access to private variables
• NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE(type, member...)
  NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_WITH_DEFAULT(type, member...) - serialization/deserialization of types without access to private variables
• NLOHMANN_JSON_SERIALIZE_ENUM(type, ...) - serialization/deserialization of enum types