From 97737f29bee6c218f6bd135879ca7ce8110fbc97 Mon Sep 17 00:00:00 2001
From: Niels Lohmann <mail@nlohmann.me>
Date: Wed, 22 Oct 2025 11:34:53 +0200
Subject: [PATCH 1/5] :recycle: address CWG issue 2521 #4956

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
---
 include/nlohmann/json.hpp        | 21 ++++-----------------
 single_include/nlohmann/json.hpp | 21 ++++-----------------
 2 files changed, 8 insertions(+), 34 deletions(-)

diff --git a/include/nlohmann/json.hpp b/include/nlohmann/json.hpp
index 8979c2d1f4..0ef7b43912 100644
--- a/include/nlohmann/json.hpp
+++ b/include/nlohmann/json.hpp
@@ -5273,11 +5273,7 @@ inline namespace json_literals
 /// @brief user-defined string literal for JSON values
 /// @sa https://json.nlohmann.me/api/basic_json/operator_literal_json/
 JSON_HEDLEY_NON_NULL(1)
-#if !defined(JSON_HEDLEY_GCC_VERSION) || JSON_HEDLEY_GCC_VERSION_CHECK(4,9,0)
-    inline nlohmann::json operator ""_json(const char* s, std::size_t n)
-#else
-    inline nlohmann::json operator "" _json(const char* s, std::size_t n)
-#endif
+inline nlohmann::json operator""_json(const char* s, std::size_t n)
 {
     return nlohmann::json::parse(s, s + n);
 }
@@ -5285,11 +5281,7 @@ JSON_HEDLEY_NON_NULL(1)
 /// @brief user-defined string literal for JSON pointer
 /// @sa https://json.nlohmann.me/api/basic_json/operator_literal_json_pointer/
 JSON_HEDLEY_NON_NULL(1)
-#if !defined(JSON_HEDLEY_GCC_VERSION) || JSON_HEDLEY_GCC_VERSION_CHECK(4,9,0)
-    inline nlohmann::json::json_pointer operator ""_json_pointer(const char* s, std::size_t n)
-#else
-    inline nlohmann::json::json_pointer operator "" _json_pointer(const char* s, std::size_t n)
-#endif
+inline nlohmann::json::json_pointer operator""_json_pointer(const char* s, std::size_t n)
 {
     return nlohmann::json::json_pointer(std::string(s, n));
 }
@@ -5353,13 +5345,8 @@ inline void swap(nlohmann::NLOHMANN_BASIC_JSON_TPL& j1, nlohmann::NLOHMANN_BASIC
 }  // namespace std
 
 #if JSON_USE_GLOBAL_UDLS
-    #if !defined(JSON_HEDLEY_GCC_VERSION) || JSON_HEDLEY_GCC_VERSION_CHECK(4,9,0)
-        using nlohmann::literals::json_literals::operator ""_json; // NOLINT(misc-unused-using-decls,google-global-names-in-headers)
-        using nlohmann::literals::json_literals::operator ""_json_pointer; //NOLINT(misc-unused-using-decls,google-global-names-in-headers)
-    #else
-        using nlohmann::literals::json_literals::operator "" _json; // NOLINT(misc-unused-using-decls,google-global-names-in-headers)
-        using nlohmann::literals::json_literals::operator "" _json_pointer; //NOLINT(misc-unused-using-decls,google-global-names-in-headers)
-    #endif
+    using nlohmann::literals::json_literals::operator""_json; // NOLINT(misc-unused-using-decls,google-global-names-in-headers)
+    using nlohmann::literals::json_literals::operator""_json_pointer; //NOLINT(misc-unused-using-decls,google-global-names-in-headers)
 #endif
 
 #include <nlohmann/detail/macro_unscope.hpp>
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index aafeaf5ae5..b73783a808 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -25376,11 +25376,7 @@ inline namespace json_literals
 /// @brief user-defined string literal for JSON values
 /// @sa https://json.nlohmann.me/api/basic_json/operator_literal_json/
 JSON_HEDLEY_NON_NULL(1)
-#if !defined(JSON_HEDLEY_GCC_VERSION) || JSON_HEDLEY_GCC_VERSION_CHECK(4,9,0)
-    inline nlohmann::json operator ""_json(const char* s, std::size_t n)
-#else
-    inline nlohmann::json operator "" _json(const char* s, std::size_t n)
-#endif
+inline nlohmann::json operator""_json(const char* s, std::size_t n)
 {
     return nlohmann::json::parse(s, s + n);
 }
@@ -25388,11 +25384,7 @@ JSON_HEDLEY_NON_NULL(1)
 /// @brief user-defined string literal for JSON pointer
 /// @sa https://json.nlohmann.me/api/basic_json/operator_literal_json_pointer/
 JSON_HEDLEY_NON_NULL(1)
-#if !defined(JSON_HEDLEY_GCC_VERSION) || JSON_HEDLEY_GCC_VERSION_CHECK(4,9,0)
-    inline nlohmann::json::json_pointer operator ""_json_pointer(const char* s, std::size_t n)
-#else
-    inline nlohmann::json::json_pointer operator "" _json_pointer(const char* s, std::size_t n)
-#endif
+inline nlohmann::json::json_pointer operator""_json_pointer(const char* s, std::size_t n)
 {
     return nlohmann::json::json_pointer(std::string(s, n));
 }
@@ -25456,13 +25448,8 @@ inline void swap(nlohmann::NLOHMANN_BASIC_JSON_TPL& j1, nlohmann::NLOHMANN_BASIC
 }  // namespace std
 
 #if JSON_USE_GLOBAL_UDLS
-    #if !defined(JSON_HEDLEY_GCC_VERSION) || JSON_HEDLEY_GCC_VERSION_CHECK(4,9,0)
-        using nlohmann::literals::json_literals::operator ""_json; // NOLINT(misc-unused-using-decls,google-global-names-in-headers)
-        using nlohmann::literals::json_literals::operator ""_json_pointer; //NOLINT(misc-unused-using-decls,google-global-names-in-headers)
-    #else
-        using nlohmann::literals::json_literals::operator "" _json; // NOLINT(misc-unused-using-decls,google-global-names-in-headers)
-        using nlohmann::literals::json_literals::operator "" _json_pointer; //NOLINT(misc-unused-using-decls,google-global-names-in-headers)
-    #endif
+    using nlohmann::literals::json_literals::operator""_json; // NOLINT(misc-unused-using-decls,google-global-names-in-headers)
+    using nlohmann::literals::json_literals::operator""_json_pointer; //NOLINT(misc-unused-using-decls,google-global-names-in-headers)
 #endif
 
 // #include <nlohmann/detail/macro_unscope.hpp>

From 1ab4f7c1ee6cb3a184251555302903afcffb0d8d Mon Sep 17 00:00:00 2001
From: Niels Lohmann <mail@nlohmann.me>
Date: Wed, 22 Oct 2025 12:35:46 +0200
Subject: [PATCH 2/5] :sparkles: add char8_t* overload for _json and
 _json_pointer #4956

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
---
 docs/mkdocs/docs/api/operator_literal_json.md   |  2 ++
 .../docs/api/operator_literal_json_pointer.md   |  2 ++
 include/nlohmann/json.hpp                       | 16 ++++++++++++++++
 single_include/nlohmann/json.hpp                | 16 ++++++++++++++++
 tests/src/unit-deserialization.cpp              | 17 +++++++++++++++++
 tests/src/unit-json_pointer.cpp                 | 14 ++++++++++++++
 6 files changed, 67 insertions(+)

diff --git a/docs/mkdocs/docs/api/operator_literal_json.md b/docs/mkdocs/docs/api/operator_literal_json.md
index a3a4bd28b5..fdf6e83695 100644
--- a/docs/mkdocs/docs/api/operator_literal_json.md
+++ b/docs/mkdocs/docs/api/operator_literal_json.md
@@ -2,6 +2,7 @@
 
 ```cpp
 json operator ""_json(const char* s, std::size_t n);
+json operator ""_json(const char8_t* s, std::size_t n);  // since C++20
 ```
 
 This operator implements a user-defined string literal for JSON objects. It can be used by adding `#!cpp _json` to a
@@ -59,3 +60,4 @@ Linear.
 
 - Added in version 1.0.0.
 - Moved to namespace `nlohmann::literals::json_literals` in 3.11.0.
+- Added `char8_t*` overload in 3.12.1.
diff --git a/docs/mkdocs/docs/api/operator_literal_json_pointer.md b/docs/mkdocs/docs/api/operator_literal_json_pointer.md
index 423678c77b..2c3d6a13a8 100644
--- a/docs/mkdocs/docs/api/operator_literal_json_pointer.md
+++ b/docs/mkdocs/docs/api/operator_literal_json_pointer.md
@@ -2,6 +2,7 @@
 
 ```cpp
 json_pointer operator ""_json_pointer(const char* s, std::size_t n);
+json_pointer operator ""_json_pointer(const char8_t* s, std::size_t n);  // since C++20
 ```
 
 This operator implements a user-defined string literal for JSON Pointers. It can be used by adding `#!cpp _json_pointer`
@@ -62,3 +63,4 @@ Linear.
 
 - Added in version 2.0.0.
 - Moved to namespace `nlohmann::literals::json_literals` in 3.11.0.
+- Added `char8_t*` overload in 3.12.1.
diff --git a/include/nlohmann/json.hpp b/include/nlohmann/json.hpp
index 0ef7b43912..284d71c79f 100644
--- a/include/nlohmann/json.hpp
+++ b/include/nlohmann/json.hpp
@@ -5278,6 +5278,15 @@ inline nlohmann::json operator""_json(const char* s, std::size_t n)
     return nlohmann::json::parse(s, s + n);
 }
 
+#if defined(__cpp_char8_t)
+JSON_HEDLEY_NON_NULL(1)
+inline nlohmann::json operator""_json(const char8_t* s, std::size_t n)
+{
+    return nlohmann::json::parse(reinterpret_cast<const char*>(s),
+                                 reinterpret_cast<const char*>(s) + n);
+}
+#endif
+
 /// @brief user-defined string literal for JSON pointer
 /// @sa https://json.nlohmann.me/api/basic_json/operator_literal_json_pointer/
 JSON_HEDLEY_NON_NULL(1)
@@ -5286,6 +5295,13 @@ inline nlohmann::json::json_pointer operator""_json_pointer(const char* s, std::
     return nlohmann::json::json_pointer(std::string(s, n));
 }
 
+#if defined(__cpp_char8_t)
+inline nlohmann::json::json_pointer operator""_json_pointer(const char8_t* s, std::size_t n)
+{
+    return nlohmann::json::json_pointer(std::string(reinterpret_cast<const char*>(s), n));
+}
+#endif
+
 }  // namespace json_literals
 }  // namespace literals
 NLOHMANN_JSON_NAMESPACE_END
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index b73783a808..32faa4c5e3 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -25381,6 +25381,15 @@ inline nlohmann::json operator""_json(const char* s, std::size_t n)
     return nlohmann::json::parse(s, s + n);
 }
 
+#if defined(__cpp_char8_t)
+JSON_HEDLEY_NON_NULL(1)
+inline nlohmann::json operator""_json(const char8_t* s, std::size_t n)
+{
+    return nlohmann::json::parse(reinterpret_cast<const char*>(s),
+                                 reinterpret_cast<const char*>(s) + n);
+}
+#endif
+
 /// @brief user-defined string literal for JSON pointer
 /// @sa https://json.nlohmann.me/api/basic_json/operator_literal_json_pointer/
 JSON_HEDLEY_NON_NULL(1)
@@ -25389,6 +25398,13 @@ inline nlohmann::json::json_pointer operator""_json_pointer(const char* s, std::
     return nlohmann::json::json_pointer(std::string(s, n));
 }
 
+#if defined(__cpp_char8_t)
+inline nlohmann::json::json_pointer operator""_json_pointer(const char8_t* s, std::size_t n)
+{
+    return nlohmann::json::json_pointer(std::string(reinterpret_cast<const char*>(s), n));
+}
+#endif
+
 }  // namespace json_literals
 }  // namespace literals
 NLOHMANN_JSON_NAMESPACE_END
diff --git a/tests/src/unit-deserialization.cpp b/tests/src/unit-deserialization.cpp
index 58fe958ea2..0c16afbd78 100644
--- a/tests/src/unit-deserialization.cpp
+++ b/tests/src/unit-deserialization.cpp
@@ -1132,6 +1132,23 @@ TEST_CASE("deserialization")
             CHECK(object_count == 4);
         }
     }
+
+    // build with C++20
+    // JSON_HAS_CPP_20
+#if defined(__cpp_char8_t)
+    SECTION("Using _json with char8_t literals #4945")
+    {
+        // Regular narrow string literal
+        auto j1 = R"({"key": "value", "num": 42})"_json;
+        CHECK(j1["key"] == "value");
+        CHECK(j1["num"] == 42);
+
+        // UTF-8 prefixed literal (C++20 and later)
+        auto j2 = u8R"({"emoji": "😀", "msg": "hello"})"_json;
+        CHECK(j2["emoji"] == "😀");
+        CHECK(j2["msg"] == "hello");
+    }
+#endif
 }
 
 // select the types to test - char8_t is only available since C++20 if and only
diff --git a/tests/src/unit-json_pointer.cpp b/tests/src/unit-json_pointer.cpp
index 149eff00a2..b36331eba3 100644
--- a/tests/src/unit-json_pointer.cpp
+++ b/tests/src/unit-json_pointer.cpp
@@ -788,4 +788,18 @@ TEST_CASE("JSON pointers")
             CHECK_FALSE(ptr_oj != ptr);
         }
     }
+
+    // build with C++20
+    // JSON_HAS_CPP_20
+#if defined(__cpp_char8_t)
+    SECTION("Using _json_pointer with char8_t literals #4945")
+    {
+        const json j = R"({"a": {"b": {"c": 123}}})"_json;
+        const auto p1 = "/a/b/c"_json_pointer;
+        CHECK(j[p1] == 123);
+
+        const auto p2 = u8"/a/b/c"_json_pointer;
+        CHECK(j[p2] == 123);
+    }
+#endif
 }

From 2adf75da66ee330090dfee5a792b18960c17433d Mon Sep 17 00:00:00 2001
From: Niels Lohmann <mail@nlohmann.me>
Date: Wed, 22 Oct 2025 16:30:08 +0200
Subject: [PATCH 3/5] :rewind: revert changes for #4945

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
---
 docs/mkdocs/docs/api/operator_literal_json.md   |  2 --
 .../docs/api/operator_literal_json_pointer.md   |  2 --
 include/nlohmann/json.hpp                       | 16 ----------------
 single_include/nlohmann/json.hpp                | 16 ----------------
 tests/src/unit-deserialization.cpp              | 17 -----------------
 tests/src/unit-json_pointer.cpp                 | 14 --------------
 6 files changed, 67 deletions(-)

diff --git a/docs/mkdocs/docs/api/operator_literal_json.md b/docs/mkdocs/docs/api/operator_literal_json.md
index fdf6e83695..a3a4bd28b5 100644
--- a/docs/mkdocs/docs/api/operator_literal_json.md
+++ b/docs/mkdocs/docs/api/operator_literal_json.md
@@ -2,7 +2,6 @@
 
 ```cpp
 json operator ""_json(const char* s, std::size_t n);
-json operator ""_json(const char8_t* s, std::size_t n);  // since C++20
 ```
 
 This operator implements a user-defined string literal for JSON objects. It can be used by adding `#!cpp _json` to a
@@ -60,4 +59,3 @@ Linear.
 
 - Added in version 1.0.0.
 - Moved to namespace `nlohmann::literals::json_literals` in 3.11.0.
-- Added `char8_t*` overload in 3.12.1.
diff --git a/docs/mkdocs/docs/api/operator_literal_json_pointer.md b/docs/mkdocs/docs/api/operator_literal_json_pointer.md
index 2c3d6a13a8..423678c77b 100644
--- a/docs/mkdocs/docs/api/operator_literal_json_pointer.md
+++ b/docs/mkdocs/docs/api/operator_literal_json_pointer.md
@@ -2,7 +2,6 @@
 
 ```cpp
 json_pointer operator ""_json_pointer(const char* s, std::size_t n);
-json_pointer operator ""_json_pointer(const char8_t* s, std::size_t n);  // since C++20
 ```
 
 This operator implements a user-defined string literal for JSON Pointers. It can be used by adding `#!cpp _json_pointer`
@@ -63,4 +62,3 @@ Linear.
 
 - Added in version 2.0.0.
 - Moved to namespace `nlohmann::literals::json_literals` in 3.11.0.
-- Added `char8_t*` overload in 3.12.1.
diff --git a/include/nlohmann/json.hpp b/include/nlohmann/json.hpp
index 284d71c79f..0ef7b43912 100644
--- a/include/nlohmann/json.hpp
+++ b/include/nlohmann/json.hpp
@@ -5278,15 +5278,6 @@ inline nlohmann::json operator""_json(const char* s, std::size_t n)
     return nlohmann::json::parse(s, s + n);
 }
 
-#if defined(__cpp_char8_t)
-JSON_HEDLEY_NON_NULL(1)
-inline nlohmann::json operator""_json(const char8_t* s, std::size_t n)
-{
-    return nlohmann::json::parse(reinterpret_cast<const char*>(s),
-                                 reinterpret_cast<const char*>(s) + n);
-}
-#endif
-
 /// @brief user-defined string literal for JSON pointer
 /// @sa https://json.nlohmann.me/api/basic_json/operator_literal_json_pointer/
 JSON_HEDLEY_NON_NULL(1)
@@ -5295,13 +5286,6 @@ inline nlohmann::json::json_pointer operator""_json_pointer(const char* s, std::
     return nlohmann::json::json_pointer(std::string(s, n));
 }
 
-#if defined(__cpp_char8_t)
-inline nlohmann::json::json_pointer operator""_json_pointer(const char8_t* s, std::size_t n)
-{
-    return nlohmann::json::json_pointer(std::string(reinterpret_cast<const char*>(s), n));
-}
-#endif
-
 }  // namespace json_literals
 }  // namespace literals
 NLOHMANN_JSON_NAMESPACE_END
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index 32faa4c5e3..b73783a808 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -25381,15 +25381,6 @@ inline nlohmann::json operator""_json(const char* s, std::size_t n)
     return nlohmann::json::parse(s, s + n);
 }
 
-#if defined(__cpp_char8_t)
-JSON_HEDLEY_NON_NULL(1)
-inline nlohmann::json operator""_json(const char8_t* s, std::size_t n)
-{
-    return nlohmann::json::parse(reinterpret_cast<const char*>(s),
-                                 reinterpret_cast<const char*>(s) + n);
-}
-#endif
-
 /// @brief user-defined string literal for JSON pointer
 /// @sa https://json.nlohmann.me/api/basic_json/operator_literal_json_pointer/
 JSON_HEDLEY_NON_NULL(1)
@@ -25398,13 +25389,6 @@ inline nlohmann::json::json_pointer operator""_json_pointer(const char* s, std::
     return nlohmann::json::json_pointer(std::string(s, n));
 }
 
-#if defined(__cpp_char8_t)
-inline nlohmann::json::json_pointer operator""_json_pointer(const char8_t* s, std::size_t n)
-{
-    return nlohmann::json::json_pointer(std::string(reinterpret_cast<const char*>(s), n));
-}
-#endif
-
 }  // namespace json_literals
 }  // namespace literals
 NLOHMANN_JSON_NAMESPACE_END
diff --git a/tests/src/unit-deserialization.cpp b/tests/src/unit-deserialization.cpp
index 0c16afbd78..58fe958ea2 100644
--- a/tests/src/unit-deserialization.cpp
+++ b/tests/src/unit-deserialization.cpp
@@ -1132,23 +1132,6 @@ TEST_CASE("deserialization")
             CHECK(object_count == 4);
         }
     }
-
-    // build with C++20
-    // JSON_HAS_CPP_20
-#if defined(__cpp_char8_t)
-    SECTION("Using _json with char8_t literals #4945")
-    {
-        // Regular narrow string literal
-        auto j1 = R"({"key": "value", "num": 42})"_json;
-        CHECK(j1["key"] == "value");
-        CHECK(j1["num"] == 42);
-
-        // UTF-8 prefixed literal (C++20 and later)
-        auto j2 = u8R"({"emoji": "😀", "msg": "hello"})"_json;
-        CHECK(j2["emoji"] == "😀");
-        CHECK(j2["msg"] == "hello");
-    }
-#endif
 }
 
 // select the types to test - char8_t is only available since C++20 if and only
diff --git a/tests/src/unit-json_pointer.cpp b/tests/src/unit-json_pointer.cpp
index b36331eba3..149eff00a2 100644
--- a/tests/src/unit-json_pointer.cpp
+++ b/tests/src/unit-json_pointer.cpp
@@ -788,18 +788,4 @@ TEST_CASE("JSON pointers")
             CHECK_FALSE(ptr_oj != ptr);
         }
     }
-
-    // build with C++20
-    // JSON_HAS_CPP_20
-#if defined(__cpp_char8_t)
-    SECTION("Using _json_pointer with char8_t literals #4945")
-    {
-        const json j = R"({"a": {"b": {"c": 123}}})"_json;
-        const auto p1 = "/a/b/c"_json_pointer;
-        CHECK(j[p1] == 123);
-
-        const auto p2 = u8"/a/b/c"_json_pointer;
-        CHECK(j[p2] == 123);
-    }
-#endif
 }

From 7fc3bea9b3354268ad4de28eada0d1de650f647c Mon Sep 17 00:00:00 2001
From: Niels Lohmann <mail@nlohmann.me>
Date: Wed, 22 Oct 2025 21:26:38 +0200
Subject: [PATCH 4/5] :green_heart: add code for GCC 4.8

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
---
 include/nlohmann/json.hpp        | 14 ++++++++++++--
 single_include/nlohmann/json.hpp | 14 ++++++++++++--
 2 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/include/nlohmann/json.hpp b/include/nlohmann/json.hpp
index 0ef7b43912..f252fca567 100644
--- a/include/nlohmann/json.hpp
+++ b/include/nlohmann/json.hpp
@@ -5273,7 +5273,12 @@ inline namespace json_literals
 /// @brief user-defined string literal for JSON values
 /// @sa https://json.nlohmann.me/api/basic_json/operator_literal_json/
 JSON_HEDLEY_NON_NULL(1)
-inline nlohmann::json operator""_json(const char* s, std::size_t n)
+#if !defined(JSON_HEDLEY_GCC_VERSION) || JSON_HEDLEY_GCC_VERSION_CHECK(4,9,0)
+    inline nlohmann::json operator""_json(const char* s, std::size_t n)
+#else
+    // GCC 4.8 requires a space between "" and suffix
+    inline nlohmann::json operator"" _json(const char* s, std::size_t n)
+#endif
 {
     return nlohmann::json::parse(s, s + n);
 }
@@ -5281,7 +5286,12 @@ inline nlohmann::json operator""_json(const char* s, std::size_t n)
 /// @brief user-defined string literal for JSON pointer
 /// @sa https://json.nlohmann.me/api/basic_json/operator_literal_json_pointer/
 JSON_HEDLEY_NON_NULL(1)
-inline nlohmann::json::json_pointer operator""_json_pointer(const char* s, std::size_t n)
+#if !defined(JSON_HEDLEY_GCC_VERSION) || JSON_HEDLEY_GCC_VERSION_CHECK(4,9,0)
+    inline nlohmann::json::json_pointer operator""_json_pointer(const char* s, std::size_t n)
+#else
+    // GCC 4.8 requires a space between "" and suffix
+    inline nlohmann::json::json_pointer operator"" _json_pointer(const char* s, std::size_t n)
+#endif
 {
     return nlohmann::json::json_pointer(std::string(s, n));
 }
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index b73783a808..2cf666ac2b 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -25376,7 +25376,12 @@ inline namespace json_literals
 /// @brief user-defined string literal for JSON values
 /// @sa https://json.nlohmann.me/api/basic_json/operator_literal_json/
 JSON_HEDLEY_NON_NULL(1)
-inline nlohmann::json operator""_json(const char* s, std::size_t n)
+#if !defined(JSON_HEDLEY_GCC_VERSION) || JSON_HEDLEY_GCC_VERSION_CHECK(4,9,0)
+    inline nlohmann::json operator""_json(const char* s, std::size_t n)
+#else
+    // GCC 4.8 requires a space between "" and suffix
+    inline nlohmann::json operator"" _json(const char* s, std::size_t n)
+#endif
 {
     return nlohmann::json::parse(s, s + n);
 }
@@ -25384,7 +25389,12 @@ inline nlohmann::json operator""_json(const char* s, std::size_t n)
 /// @brief user-defined string literal for JSON pointer
 /// @sa https://json.nlohmann.me/api/basic_json/operator_literal_json_pointer/
 JSON_HEDLEY_NON_NULL(1)
-inline nlohmann::json::json_pointer operator""_json_pointer(const char* s, std::size_t n)
+#if !defined(JSON_HEDLEY_GCC_VERSION) || JSON_HEDLEY_GCC_VERSION_CHECK(4,9,0)
+    inline nlohmann::json::json_pointer operator""_json_pointer(const char* s, std::size_t n)
+#else
+    // GCC 4.8 requires a space between "" and suffix
+    inline nlohmann::json::json_pointer operator"" _json_pointer(const char* s, std::size_t n)
+#endif
 {
     return nlohmann::json::json_pointer(std::string(s, n));
 }

From 81d859f5a93241405ffef811338d0ce931191597 Mon Sep 17 00:00:00 2001
From: Niels Lohmann <mail@nlohmann.me>
Date: Wed, 22 Oct 2025 22:11:18 +0200
Subject: [PATCH 5/5] :green_heart: add code for GCC 4.8

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
---
 include/nlohmann/json.hpp        | 10 ++++++++--
 single_include/nlohmann/json.hpp | 10 ++++++++--
 2 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/include/nlohmann/json.hpp b/include/nlohmann/json.hpp
index f252fca567..f86e8d4944 100644
--- a/include/nlohmann/json.hpp
+++ b/include/nlohmann/json.hpp
@@ -5355,8 +5355,14 @@ inline void swap(nlohmann::NLOHMANN_BASIC_JSON_TPL& j1, nlohmann::NLOHMANN_BASIC
 }  // namespace std
 
 #if JSON_USE_GLOBAL_UDLS
-    using nlohmann::literals::json_literals::operator""_json; // NOLINT(misc-unused-using-decls,google-global-names-in-headers)
-    using nlohmann::literals::json_literals::operator""_json_pointer; //NOLINT(misc-unused-using-decls,google-global-names-in-headers)
+    #if !defined(JSON_HEDLEY_GCC_VERSION) || JSON_HEDLEY_GCC_VERSION_CHECK(4,9,0)
+        using nlohmann::literals::json_literals::operator""_json; // NOLINT(misc-unused-using-decls,google-global-names-in-headers)
+        using nlohmann::literals::json_literals::operator""_json_pointer; //NOLINT(misc-unused-using-decls,google-global-names-in-headers)
+    #else
+        // GCC 4.8 requires a space between "" and suffix
+        using nlohmann::literals::json_literals::operator"" _json; // NOLINT(misc-unused-using-decls,google-global-names-in-headers)
+        using nlohmann::literals::json_literals::operator"" _json_pointer; //NOLINT(misc-unused-using-decls,google-global-names-in-headers)
+    #endif
 #endif
 
 #include <nlohmann/detail/macro_unscope.hpp>
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index 2cf666ac2b..1f2fcfccd5 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -25458,8 +25458,14 @@ inline void swap(nlohmann::NLOHMANN_BASIC_JSON_TPL& j1, nlohmann::NLOHMANN_BASIC
 }  // namespace std
 
 #if JSON_USE_GLOBAL_UDLS
-    using nlohmann::literals::json_literals::operator""_json; // NOLINT(misc-unused-using-decls,google-global-names-in-headers)
-    using nlohmann::literals::json_literals::operator""_json_pointer; //NOLINT(misc-unused-using-decls,google-global-names-in-headers)
+    #if !defined(JSON_HEDLEY_GCC_VERSION) || JSON_HEDLEY_GCC_VERSION_CHECK(4,9,0)
+        using nlohmann::literals::json_literals::operator""_json; // NOLINT(misc-unused-using-decls,google-global-names-in-headers)
+        using nlohmann::literals::json_literals::operator""_json_pointer; //NOLINT(misc-unused-using-decls,google-global-names-in-headers)
+    #else
+        // GCC 4.8 requires a space between "" and suffix
+        using nlohmann::literals::json_literals::operator"" _json; // NOLINT(misc-unused-using-decls,google-global-names-in-headers)
+        using nlohmann::literals::json_literals::operator"" _json_pointer; //NOLINT(misc-unused-using-decls,google-global-names-in-headers)
+    #endif
 #endif
 
 // #include <nlohmann/detail/macro_unscope.hpp>