Standard Template Library Support

Glaze uses C++20 concepts to not only support the standard template library, but also other libraries or custom types that conform to the same interface.

Array Types

Array types logically convert to JSON array values. Concepts are used to allow various containers and even user containers if they match standard library interfaces.

• std::tuple
• std::array
• std::vector
• std::deque
• std::list
• std::forward_list
• std::span
• std::set
• std::unordered_set

Object Types

• glz::object (compile time mixed types)
• std::map
• std::unordered_map
• glz::ordered_small_map (insertion-order, string keys, compact)
• glz::ordered_map (insertion-order, generic keys, Robin Hood hashing)

See Ordered Maps for detailed comparison and usage.

Variants

• std::variant

Variants support auto-deduction and tagged types. Smart pointers (std::unique_ptr, std::shared_ptr) are fully supported as variant alternatives, including with tagged variants.

See Variant Handling for more information.

Nullable Types

• std::unique_ptr
• std::shared_ptr
• std::optional
• Raw pointers (T*)

Nullable types may be allocated by valid input or nullified by the null keyword. Smart pointers can also be used as variant alternatives (e.g., std::variant<std::unique_ptr<A>, std::unique_ptr<B>>), see Variant Handling for details.

String Types

• std::string

• std::string_view

• std::filesystem::path

  • Note that std::filesystem::path does not work with pure reflection on GCC and MSVC (requires a glz::meta)

• std::bitset

std::bitset<8> b = 0b10101010;
// will be serialized as a string: "10101010"

Chrono Types

• std::chrono::duration<Rep, Period> - serializes as numeric count
• std::chrono::system_clock::time_point - serializes as ISO 8601 string (JSON) or native datetime (TOML)
• std::chrono::steady_clock::time_point - serializes as numeric count
• std::chrono::high_resolution_clock::time_point - serializes as numeric count
• std::chrono::year_month_day - serializes as TOML Local Date
• std::chrono::hh_mm_ss<Duration> - serializes as TOML Local Time

See Chrono Support for detailed information about time serialization and epoch_time wrappers. See TOML Datetime Support for TOML-specific native datetime format.

std::expected

std::expected is supported where the expected value is treated as it would typically be handled in JSON, and the unexpected value is treated as a JSON object with the unexpected value referred to by an "unexpected" key.

Example of unexpected:

{"unexpected": "my error string"}