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Fix missing exports from json.cppm #5137

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Merged
nlohmann merged 7 commits into from
May 8, 2026
Merged

Fix missing exports from json.cppm #5137

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b471653
Fix missing exports from `json.cppm`
mikomikotaishi Apr 15, 2026
507b346
Update documentation to describe what symbols are exported
mikomikotaishi Apr 19, 2026
e35f566
Add mention of `std` symbols
mikomikotaishi Apr 19, 2026
79c7fc9
Add `json_literals` inline namespace to `using` statement
mikomikotaishi Apr 19, 2026
026df83
Remove internals (`nlohmann::detail::*`) from module
mikomikotaishi Apr 20, 2026
244d5b3
Omit internals (`nlohmann::detail::*`) from modules documentation
mikomikotaishi Apr 20, 2026
c639b51
Restore `nlohmann::detail` symbols with mention of the MSVC bug
mikomikotaishi Apr 20, 2026
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16 changes: 14 additions & 2 deletions docs/mkdocs/docs/features/modules.md
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Expand Up @@ -24,11 +24,23 @@ json data = json::parse(f);
```

## Modules do not export macros
It should be noted that as modules do not export macros, the `nlohmann.json` module will not export any macros, but rather only the following symbols:
It should be noted that as modules do not export macros, the `nlohmann.json` module will not export any macros.

## Exported symbols
Only the following symbols are exported from `nlohmann.json`:
- `nlohmann::adl_serializer`
- `nlohmann::basic_json`
- `nlohmann::json`
- `nlohmann::json_pointer`
- `nlohmann::ordered_map`
- `nlohmann::ordered_json`
- `nlohmann::ordered_map`
- `nlohmann::to_string`
- `nlohmann::detail::json_sax_dom_callback_parser`
- `nlohmann::detail::unknown_size`
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- `nlohmann::literals::json_literals::operator""_json`
- `nlohmann::literals::json_literals::operator""_json_pointer`

The following specialisations of `std` symbols are also exported:
- `std::hash`
- `std::less`
- `std::swap`
54 changes: 35 additions & 19 deletions src/modules/json.cppm
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@@ -1,32 +1,48 @@
// __ _____ _____ _____
// __| | __| | | | JSON for Modern C++
// | | |__ | | | | | | version 3.12.0
// |_____|_____|_____|_|___| https://github.com/nlohmann/json
//
// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
// SPDX-License-Identifier: MIT

module;

#include <nlohmann/json.hpp>

export module nlohmann.json;

export namespace nlohmann {
using ::nlohmann::adl_serializer;
using ::nlohmann::basic_json;
using ::nlohmann::json;
using ::nlohmann::json_pointer;
using ::nlohmann::ordered_json;
using ::nlohmann::ordered_map;
} // namespace nlohmann

export
NLOHMANN_JSON_NAMESPACE_BEGIN

using NLOHMANN_JSON_NAMESPACE::adl_serializer;
using NLOHMANN_JSON_NAMESPACE::basic_json;
using NLOHMANN_JSON_NAMESPACE::json;
using NLOHMANN_JSON_NAMESPACE::json_pointer;
using NLOHMANN_JSON_NAMESPACE::ordered_json;
using NLOHMANN_JSON_NAMESPACE::ordered_map;
using NLOHMANN_JSON_NAMESPACE::to_string;

inline namespace literals
{
inline namespace json_literals
{
using NLOHMANN_JSON_NAMESPACE::literals::json_literals::operator""_json;
using NLOHMANN_JSON_NAMESPACE::literals::json_literals::operator""_json_pointer;
} // namespace json_literals
} // namespace literals

namespace detail
{
export using NLOHMANN_JSON_NAMESPACE::detail::json_sax_dom_callback_parser;
export using NLOHMANN_JSON_NAMESPACE::detail::unknown_size;
using NLOHMANN_JSON_NAMESPACE::detail::json_sax_dom_callback_parser;
using NLOHMANN_JSON_NAMESPACE::detail::unknown_size;
} // namespace detail

export using NLOHMANN_JSON_NAMESPACE::adl_serializer;
export using NLOHMANN_JSON_NAMESPACE::basic_json;
export using NLOHMANN_JSON_NAMESPACE::json;
export using NLOHMANN_JSON_NAMESPACE::json_pointer;
export using NLOHMANN_JSON_NAMESPACE::ordered_json;
export using NLOHMANN_JSON_NAMESPACE::ordered_map;
export using NLOHMANN_JSON_NAMESPACE::to_string;

NLOHMANN_JSON_NAMESPACE_END

export namespace std
{
using std::hash;
using std::less;
using std::swap;
} // namespace std
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