Update preprocessor `#else` and `#endif` comment (#3950)

Co-authored-by: Stephan T. Lavavej <stl@nuwen.net>

stl/inc/__msvc_all_public_headers.hpp

@@ -22,7 +22,7 @@
 // VSO-768746: mbctype.h macroizes _MS, _MP, _M1, and _M2. Include it first for test coverage.
 #ifndef _MSVC_TESTING_NVCC
 #include <mbctype.h>
-#endif // _MSVC_TESTING_NVCC
+#endif // !defined(_MSVC_TESTING_NVCC)
 
 #if 1 // TRANSITION, OS-17090155 (UCRT)
 #define _CRT_DECLARE_NONSTDC_NAMES 0
@@ -30,7 +30,7 @@
 #include <sys/stat.h>
 #include <sys/timeb.h>
 #include <sys/utime.h>
-#endif // _MSVC_TESTING_NVCC
+#endif // !defined(_MSVC_TESTING_NVCC)
 #undef _CRT_DECLARE_NONSTDC_NAMES
 #endif // TRANSITION, OS-17090155 (UCRT)
 
@@ -154,7 +154,7 @@
 #include <shared_mutex>
 #include <stop_token>
 #include <thread>
-#endif // _M_CEE_PURE
+#endif // !defined(_M_CEE_PURE)
 
 // Non-Core C Wrapper Headers
 #include <ccomplex>
@@ -176,7 +176,7 @@
 #include <experimental/unordered_set>
 #include <experimental/vector>
 
-#endif // _CORE_HEADERS_ONLY
+#endif // !defined(_CORE_HEADERS_ONLY)
 
 #ifndef _MSVC_TESTING_NVCC
 #include <assert.h>
@@ -229,12 +229,12 @@
 #ifndef _CORE_HEADERS_ONLY
 #include <complex.h>
 #include <new.h>
-#endif // _CORE_HEADERS_ONLY
+#endif // !defined(_CORE_HEADERS_ONLY)
 
 #ifndef _M_CEE_PURE
 #include <fpieee.h>
-#endif // _M_CEE_PURE
-#endif // _MSVC_TESTING_NVCC
+#endif // !defined(_M_CEE_PURE)
+#endif // !defined(_MSVC_TESTING_NVCC)
 
 #if !(defined(__CUDACC__) && defined(__clang__))
 #pragma pop_macro("new")

stl/inc/__msvc_filebuf.hpp

@@ -34,9 +34,9 @@ namespace filesystem {
 #ifndef _FSTREAM_SUPPORTS_EXPERIMENTAL_FILESYSTEM
 #ifdef _M_CEE
 #define _FSTREAM_SUPPORTS_EXPERIMENTAL_FILESYSTEM 0
-#else // _M_CEE
+#else // ^^^ defined(_M_CEE) / !defined(_M_CEE) vvv
 #define _FSTREAM_SUPPORTS_EXPERIMENTAL_FILESYSTEM 1
-#endif // _M_CEE
+#endif // ^^^ !defined(_M_CEE) ^^^
 #endif // _FSTREAM_SUPPORTS_EXPERIMENTAL_FILESYSTEM
 
 #if _FSTREAM_SUPPORTS_EXPERIMENTAL_FILESYSTEM

stl/inc/__msvc_int128.hpp

@@ -160,7 +160,7 @@ struct
         constexpr auto _Int_max = static_cast<size_t>(INT_MAX);
         _STL_INTERNAL_STATIC_ASSERT(__m <= _Int_max);
         _STL_INTERNAL_STATIC_ASSERT(__n <= _Int_max);
-#endif // _ENABLE_STL_INTERNAL_CHECK
+#endif // defined(_ENABLE_STL_INTERNAL_CHECK)
 
         for (auto& _Elem : __w) {
             _Elem = 0;

stl/inc/__msvc_sanitizer_annotate_container.hpp

@@ -24,7 +24,7 @@ _STL_DISABLE_CLANG_WARNINGS
 #define _ACTIVATE_VECTOR_ANNOTATION
 #define _INSERT_VECTOR_ANNOTATION
 
-#elif defined(__clang__) // ^^^ __SANITIZE_ADDRESS__ / __clang__ vvv
+#elif defined(__clang__) // ^^^ defined(__SANITIZE_ADDRESS__) / defined(__clang__) vvv
 
 #if __has_feature(address_sanitizer)
 #define _ACTIVATE_STRING_ANNOTATION
@@ -34,41 +34,41 @@ _STL_DISABLE_CLANG_WARNINGS
 #pragma comment(linker, "/INFERASANLIBS")
 #endif // __has_feature(address_sanitizer)
 
-#else // ^^^ __clang__ / !__clang__ && !__SANITIZE_ADDRESS__ vvv
+#else // ^^^ defined(__clang__) / !defined(__clang__) && !defined(__SANITIZE_ADDRESS__) vvv
 
 #ifdef _ANNOTATE_STRING
 #define _INSERT_STRING_ANNOTATION
-#endif // _ANNOTATE_STRING
+#endif // defined(_ANNOTATE_STRING)
 #ifdef _ANNOTATE_VECTOR
 #define _INSERT_VECTOR_ANNOTATION
-#endif // _ANNOTATE_VECTOR
+#endif // defined(_ANNOTATE_VECTOR)
 
-#endif // __SANITIZE_ADDRESS__
+#endif // ^^^ !defined(__clang__) && !defined(__SANITIZE_ADDRESS__) ^^^
 
 #ifdef _DISABLE_STRING_ANNOTATION
 #undef _ACTIVATE_STRING_ANNOTATION
 #undef _INSERT_STRING_ANNOTATION
-#endif // _DISABLE_STRING_ANNOTATION
+#endif // defined(_DISABLE_STRING_ANNOTATION)
 #ifdef _DISABLE_VECTOR_ANNOTATION
 #undef _ACTIVATE_VECTOR_ANNOTATION
 #undef _INSERT_VECTOR_ANNOTATION
-#endif // _DISABLE_VECTOR_ANNOTATION
+#endif // defined(_DISABLE_VECTOR_ANNOTATION)
 
 #ifndef _INSERT_STRING_ANNOTATION
 #pragma detect_mismatch("annotate_string", "0")
-#endif // !_INSERT_STRING_ANNOTATION
+#endif // !defined(_INSERT_STRING_ANNOTATION)
 #ifndef _INSERT_VECTOR_ANNOTATION
 #pragma detect_mismatch("annotate_vector", "0")
-#endif // !_INSERT_VECTOR_ANNOTATION
+#endif // !defined(_INSERT_VECTOR_ANNOTATION)
 
 #ifdef _ACTIVATE_STRING_ANNOTATION
 #pragma comment(lib, "stl_asan")
 #pragma detect_mismatch("annotate_string", "1")
-#endif // _ACTIVATE_STRING_ANNOTATION
+#endif // defined(_ACTIVATE_STRING_ANNOTATION)
 #ifdef _ACTIVATE_VECTOR_ANNOTATION
 #pragma comment(lib, "stl_asan")
 #pragma detect_mismatch("annotate_vector", "1")
-#endif // _ACTIVATE_VECTOR_ANNOTATION
+#endif // defined(_ACTIVATE_VECTOR_ANNOTATION)
 
 #undef _ACTIVATE_STRING_ANNOTATION
 #undef _ACTIVATE_VECTOR_ANNOTATION
@@ -123,7 +123,7 @@ void __cdecl __sanitizer_annotate_contiguous_container(
 
 #endif // insert asan annotations
 
-#endif // !_M_CEE_PURE && asan not disabled
+#endif // !defined(_M_CEE_PURE) && asan not disabled
 
 #pragma pop_macro("new")
 _STL_RESTORE_CLANG_WARNINGS

stl/inc/array

@@ -107,7 +107,7 @@ public:
     _NODISCARD _CONSTEXPR17 bool operator<(const _Array_const_iterator& _Right) const noexcept {
         return _Ptr < _Right._Ptr;
     }
-#endif // !_HAS_CXX20
+#endif // ^^^ !_HAS_CXX20 ^^^
 
     using _Prevent_inheriting_unwrap = _Array_const_iterator;
 
@@ -213,7 +213,7 @@ private:
         _Compat(_Right);
         return _Idx < _Right._Idx;
     }
-#endif // !_HAS_CXX20
+#endif // ^^^ !_HAS_CXX20 ^^^
 
     _CONSTEXPR17 void _Compat(const _Array_const_iterator& _Right) const noexcept { // test for compatible iterator pair
         _STL_VERIFY(_Ptr == _Right._Ptr, "array iterators incompatible");
@@ -237,7 +237,7 @@ private:
 private:
     pointer _Ptr; // beginning of array
     size_t _Idx; // offset into array
-#endif // _ITERATOR_DEBUG_LEVEL == 0
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL != 0 ^^^
 
 public:
     _NODISCARD _CONSTEXPR17 _Array_const_iterator operator+(const ptrdiff_t _Off) const noexcept {

stl/inc/atomic

@@ -10,7 +10,7 @@
 
 #ifdef _M_CEE_PURE
 #error <atomic> is not supported when compiling with /clr:pure.
-#endif // _M_CEE_PURE
+#endif // defined(_M_CEE_PURE)
 
 #include <cstddef>
 #include <cstdint>
@@ -42,15 +42,15 @@ extern "C" _NODISCARD unsigned char __stdcall __std_atomic_compare_exchange_128(
     _Inout_bytecount_(16) long long* _ComparandResult) noexcept;
 extern "C" _NODISCARD char __stdcall __std_atomic_has_cmpxchg16b() noexcept;
 #define _STD_COMPARE_EXCHANGE_128 __std_atomic_compare_exchange_128
-#endif // _STD_ATOMIC_ALWAYS_USE_CMPXCHG16B == 1
-#endif // _WIN64
+#endif // ^^^ _STD_ATOMIC_ALWAYS_USE_CMPXCHG16B == 0 ^^^
+#endif // defined(_WIN64)
 
 // Controls whether atomic::is_always_lock_free triggers for sizeof(void *) or 2 * sizeof(void *)
 #if _STD_ATOMIC_ALWAYS_USE_CMPXCHG16B == 1 || !defined(_M_X64) || defined(_M_ARM64EC)
 #define _ATOMIC_HAS_DCAS 1
 #else // ^^^ We always have DCAS / We only sometimes have DCAS vvv
 #define _ATOMIC_HAS_DCAS 0
-#endif // _STD_ATOMIC_ALWAYS_USE_CMPXCHG16B == 1 || !defined(_M_X64) || defined(_M_ARM64EC)
+#endif // ^^^ We only sometimes have DCAS ^^^
 
 // Controls whether ARM64 ldar/ldapr/stlr should be used
 #ifndef _STD_ATOMIC_USE_ARM64_LDAR_STLR
@@ -62,7 +62,7 @@ extern "C" _NODISCARD char __stdcall __std_atomic_has_cmpxchg16b() noexcept;
 #endif // ^^^ __load_acquire/__stlr intrinsics are available ^^^
 #else // ^^^ ARM64/ARM64EC / Other architectures vvv
 #define _STD_ATOMIC_USE_ARM64_LDAR_STLR 0
-#endif // defined(_M_ARM64) || defined(_M_ARM64EC)
+#endif // ^^^ Other architectures ^^^
 #endif // _STD_ATOMIC_USE_ARM64_LDAR_STLR
 
 #define ATOMIC_BOOL_LOCK_FREE 2
@@ -219,9 +219,9 @@ extern "C" inline void _Check_memory_order(const unsigned int _Order) noexcept {
     __stlr##_Width(                                                                                               \
         reinterpret_cast<volatile unsigned __int##_Width*>(_Ptr), static_cast<unsigned __int##_Width>(_Desired)); \
     _Memory_barrier();
-#else
+#else // ^^^ _STD_ATOMIC_USE_ARM64_LDAR_STLR == 1 / _STD_ATOMIC_USE_ARM64_LDAR_STLR == 0 vvv
 #define _ATOMIC_STORE_SEQ_CST_ARM64 _ATOMIC_STORE_SEQ_CST_ARM
-#endif
+#endif // ^^^ _STD_ATOMIC_USE_ARM64_LDAR_STLR == 0 ^^^
 
 #define _ATOMIC_STORE_SEQ_CST_X86_X64(_Width, _Ptr, _Desired) (void) _InterlockedExchange##_Width((_Ptr), (_Desired));
 #define _ATOMIC_STORE_32_SEQ_CST_X86_X64(_Ptr, _Desired) \
@@ -250,7 +250,7 @@ extern "C" inline void _Check_memory_order(const unsigned int _Order) noexcept {
 #endif // ^^^ x64 ^^^
 #else // ^^^ x86/x64 / Unsupported hardware vvv
 #error "Unsupported hardware"
-#endif
+#endif // ^^^ Unsupported hardware ^^^
 
 #pragma warning(push)
 #pragma warning(disable : 6001) // "Using uninitialized memory '_Guard'"
@@ -276,7 +276,7 @@ extern "C" inline void _Atomic_thread_fence(const unsigned int _Order) noexcept
     _Memory_barrier();
 #else // ^^^ ARM32/ARM64/ARM64EC / unsupported hardware vvv
 #error Unsupported hardware
-#endif // unsupported hardware
+#endif // ^^^ unsupported hardware ^^^
 }
 #pragma warning(pop)
 
@@ -469,7 +469,7 @@ struct _Atomic_padded<_Ty&, false> {
     _Ty& _Value;
 };
 
-#endif // TRANSITION, ABI
+#endif // ^^^ break ABI ^^^
 
 template <class _Ty>
 struct _Atomic_storage_types {
@@ -487,7 +487,7 @@ struct _Atomic_storage_types<_Ty&> {
 template <class _Ty, size_t = sizeof(remove_reference_t<_Ty>)>
 #else // ^^^ don't break ABI / break ABI vvv
 template <class _Ty, size_t = _Atomic_storage_traits<_Ty>::_Storage_size>
-#endif // TRANSITION, ABI
+#endif // ^^^ break ABI ^^^
 struct _Atomic_storage;
 
 #if _HAS_CXX20
@@ -706,7 +706,7 @@ struct _Atomic_storage {
                             return;
                         }
                     } else
-#endif // #if _CMPXCHG_MASK_OUT_PADDING_BITS
+#endif // _CMPXCHG_MASK_OUT_PADDING_BITS
                     {
                         return;
                     }
@@ -743,7 +743,7 @@ public:
 #else // ^^^ don't break ABI / break ABI vvv
     _Ty _Storage;
     mutable _Smtx_t _Mutex{};
-#endif // TRANSITION, ABI
+#endif // ^^^ break ABI ^^^
 };
 
 template <class _Ty>
@@ -787,10 +787,10 @@ struct _Atomic_storage<_Ty, 1> { // lock-free using 1-byte intrinsics
         char _As_bytes;
 #if _STD_ATOMIC_USE_ARM64_LDAR_STLR == 1
         _ATOMIC_LOAD_ARM64(_As_bytes, 8, _Mem, static_cast<unsigned int>(_Order))
-#else
+#else // ^^^ _STD_ATOMIC_USE_ARM64_LDAR_STLR == 1 / _STD_ATOMIC_USE_ARM64_LDAR_STLR == 0 vvv
         _As_bytes = __iso_volatile_load8(_Mem);
         _ATOMIC_POST_LOAD_BARRIER_AS_NEEDED(static_cast<unsigned int>(_Order))
-#endif
+#endif // ^^^ _STD_ATOMIC_USE_ARM64_LDAR_STLR == 0 ^^^
         return reinterpret_cast<_TVal&>(_As_bytes);
     }
 
@@ -895,10 +895,10 @@ struct _Atomic_storage<_Ty, 2> { // lock-free using 2-byte intrinsics
         short _As_bytes;
 #if _STD_ATOMIC_USE_ARM64_LDAR_STLR == 1
         _ATOMIC_LOAD_ARM64(_As_bytes, 16, _Mem, static_cast<unsigned int>(_Order))
-#else
+#else // ^^^ _STD_ATOMIC_USE_ARM64_LDAR_STLR == 1 / _STD_ATOMIC_USE_ARM64_LDAR_STLR == 0 vvv
         _As_bytes = __iso_volatile_load16(_Mem);
         _ATOMIC_POST_LOAD_BARRIER_AS_NEEDED(static_cast<unsigned int>(_Order))
-#endif
+#endif // ^^^ _STD_ATOMIC_USE_ARM64_LDAR_STLR == 0 ^^^
         return reinterpret_cast<_TVal&>(_As_bytes);
     }
 
@@ -1002,10 +1002,10 @@ struct _Atomic_storage<_Ty, 4> { // lock-free using 4-byte intrinsics
         int _As_bytes;
 #if _STD_ATOMIC_USE_ARM64_LDAR_STLR == 1
         _ATOMIC_LOAD_ARM64(_As_bytes, 32, _Mem, static_cast<unsigned int>(_Order))
-#else
+#else // ^^^ _STD_ATOMIC_USE_ARM64_LDAR_STLR == 1 / _STD_ATOMIC_USE_ARM64_LDAR_STLR == 0 vvv
         _As_bytes = __iso_volatile_load32(_Mem);
         _ATOMIC_POST_LOAD_BARRIER_AS_NEEDED(static_cast<unsigned int>(_Order))
-#endif
+#endif // ^^^ _STD_ATOMIC_USE_ARM64_LDAR_STLR == 0 ^^^
         return reinterpret_cast<_TVal&>(_As_bytes);
     }
 
@@ -1122,7 +1122,7 @@ struct _Atomic_storage<_Ty, 8> { // lock-free using 8-byte intrinsics
 #endif
 
         _ATOMIC_POST_LOAD_BARRIER_AS_NEEDED(static_cast<unsigned int>(_Order))
-#endif // _STD_ATOMIC_USE_ARM64_LDAR_STLR == 1
+#endif // ^^^ _STD_ATOMIC_USE_ARM64_LDAR_STLR != 1 ^^^
         return reinterpret_cast<_TVal&>(_As_bytes);
     }
 
@@ -1677,7 +1677,7 @@ _INLINE_VAR constexpr bool _Is_always_lock_free = _TypeSize <= 2 * sizeof(void*)
 template <size_t _TypeSize>
 _INLINE_VAR constexpr bool _Is_always_lock_free = _TypeSize <= sizeof(void*);
 #endif // _ATOMIC_HAS_DCAS
-#endif // break ABI
+#endif // ^^^ break ABI ^^^
 
 template <class _Ty, bool _Is_lock_free = _Is_always_lock_free<sizeof(_Ty)>>
 _INLINE_VAR constexpr bool _Deprecate_non_lock_free_volatile = true;
@@ -2010,7 +2010,7 @@ struct _Atomic_pointer : _Atomic_storage<_Ty> {
 #else // ^^^ 32 bits / 64 bits vvv
         _ATOMIC_CHOOSE_INTRINSIC(static_cast<unsigned int>(_Order), _Result, _InterlockedExchangeAdd64,
             _Atomic_address_as<long long>(this->_Storage), _Shift_bytes);
-#endif // hardware
+#endif // ^^^ 64 bits ^^^
         return reinterpret_cast<_Ty>(_Result);
     }
 
@@ -2106,7 +2106,7 @@ struct _Atomic_pointer<_Ty&> : _Atomic_storage<_Ty&> {
 #else // ^^^ 32 bits / 64 bits vvv
         _ATOMIC_CHOOSE_INTRINSIC(static_cast<unsigned int>(_Order), _Result, _InterlockedExchangeAdd64,
             _Atomic_address_as<long long>(this->_Storage), _Shift_bytes);
-#endif // hardware
+#endif // ^^^ 64 bits ^^^
         return reinterpret_cast<_Ty>(_Result);
     }
 
@@ -2159,7 +2159,7 @@ using _Choose_atomic_base_t =
 #else // ^^^ _HAS_CXX20 / !_HAS_CXX20 vvv
 template <class _TVal, class _Ty = _TVal>
 using _Choose_atomic_base_t = _Choose_atomic_base2_t<_TVal, _Ty>;
-#endif // _HAS_CXX20
+#endif // ^^^ !_HAS_CXX20 ^^^
 
 _EXPORT_STD template <class _Ty>
 struct atomic : _Choose_atomic_base_t<_Ty> { // atomic value
@@ -2200,7 +2200,7 @@ public:
         return sizeof(_Ty) <= sizeof(void*) || (sizeof(_Ty) <= 2 * sizeof(void*) && __std_atomic_has_cmpxchg16b());
 #endif // _ATOMIC_HAS_DCAS
     }
-#endif // TRANSITION, ABI
+#endif // ^^^ break ABI ^^^
 
     _NODISCARD bool is_lock_free() const noexcept {
         return static_cast<const volatile atomic*>(this)->is_lock_free();
@@ -2885,7 +2885,7 @@ _EXPORT_STD struct atomic_flag { // flag with test-and-set semantics
     atomic<long> _Storage;
 #else // ^^^ don't break ABI / break ABI vvv
     atomic<bool> _Storage;
-#endif // TRANSITION, ABI
+#endif // ^^^ break ABI ^^^
 };
 
 #if _HAS_CXX20

stl/inc/bitset

@@ -74,7 +74,7 @@ private:
         (void) _Pos;
 #else // ^^^ _ITERATOR_DEBUG_LEVEL == 0 / _ITERATOR_DEBUG_LEVEL != 0 vvv
         _STL_VERIFY(_Pos < _Bits, "bitset index outside range");
-#endif // _ITERATOR_DEBUG_LEVEL == 0
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL != 0 ^^^
     }
 
     constexpr bool _Subscript(size_t _Pos) const noexcept {

stl/inc/charconv

@@ -2609,6 +2609,6 @@ _STD_END
 _STL_RESTORE_CLANG_WARNINGS
 #pragma warning(pop)
 #pragma pack(pop)
-#endif // _HAS_CXX17
+#endif // ^^^ _HAS_CXX17 ^^^
 #endif // _STL_COMPILER_PREPROCESSOR
 #endif // _CHARCONV_

stl/inc/condition_variable

@@ -24,7 +24,7 @@ _STL_DISABLE_CLANG_WARNINGS
 
 #ifdef _M_CEE_PURE
 #error <condition_variable> is not supported when compiling with /clr:pure.
-#endif // _M_CEE_PURE
+#endif // defined(_M_CEE_PURE)
 
 _STD_BEGIN
 template <class _Lock>

stl/inc/coroutine

@@ -263,7 +263,7 @@ _STL_RESTORE_CLANG_WARNINGS
 #pragma warning(pop)
 #pragma pack(pop)
 
-#endif // <coroutine> is available
-#endif // ^^^ no /await ^^^
+#endif // ^^^ defined(__cpp_lib_coroutine) ^^^
+#endif // ^^^ !defined(_RESUMABLE_FUNCTIONS_SUPPORTED) ^^^
 #endif // _STL_COMPILER_PREPROCESSOR
 #endif // _COROUTINE_

stl/inc/deque

@@ -137,7 +137,7 @@ public:
     _NODISCARD bool operator>=(const _Deque_unchecked_const_iterator& _Right) const noexcept {
         return !(*this < _Right);
     }
-#endif // !_HAS_CXX20
+#endif // ^^^ !_HAS_CXX20 ^^^
 
     const _Container_base12* _Getcont() const noexcept { // get container pointer
         return _Mycont;
@@ -383,7 +383,7 @@ public:
     _NODISCARD bool operator>=(const _Deque_const_iterator& _Right) const noexcept {
         return !(*this < _Right);
     }
-#endif // !_HAS_CXX20
+#endif // ^^^ !_HAS_CXX20 ^^^
 
     void _Compat(const _Deque_const_iterator& _Right) const noexcept { // test for compatible iterator pair
 #if _ITERATOR_DEBUG_LEVEL == 0
@@ -414,7 +414,7 @@ public:
                 _Mycont->_Myoff <= this->_Myoff + _Off && this->_Myoff + _Off <= _Mycont->_Myoff + _Mycont->_Mysize,
                 "cannot seek deque iterator out of range");
         }
-#endif // _ITERATOR_DEBUG_LEVEL == 0
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL != 0 ^^^
     }
 
 #if _ITERATOR_DEBUG_LEVEL != 0

stl/inc/exception

@@ -203,7 +203,7 @@ _EXPORT_STD using _STDEXT bad_exception;
 
 _STD_END
 
-#endif // _HAS_EXCEPTIONS
+#endif // ^^^ !_HAS_EXCEPTIONS ^^^
 
 extern "C++" _CRTIMP2_PURE void __CLRCALL_PURE_OR_CDECL __ExceptionPtrCreate(_Out_ void*) noexcept;
 extern "C++" _CRTIMP2_PURE void __CLRCALL_PURE_OR_CDECL __ExceptionPtrDestroy(_Inout_ void*) noexcept;

stl/inc/execution

@@ -5217,6 +5217,6 @@ _STD_END
 _STL_RESTORE_CLANG_WARNINGS
 #pragma warning(pop)
 #pragma pack(pop)
-#endif // _HAS_CXX17
+#endif // ^^^ _HAS_CXX17 ^^^
 #endif // _STL_COMPILER_PREPROCESSOR
 #endif // _EXECUTION_

stl/inc/experimental/generator

@@ -121,7 +121,7 @@ namespace experimental {
                     _STD exchange(_Coro, nullptr).promise()._Rethrow_if_exception();
 #else // ^^^ defined(_CPPUNWIND) / !defined(_CPPUNWIND) vvv
                     _Coro = nullptr;
-#endif // _CPPUNWIND
+#endif // ^^^ !defined(_CPPUNWIND) ^^^
                 }
 
                 return *this;
@@ -156,7 +156,7 @@ namespace experimental {
                 if (_Coro.done()) {
 #ifdef _CPPUNWIND
                     _Coro.promise()._Rethrow_if_exception();
-#endif // _CPPUNWIND
+#endif // ^^^ defined(_CPPUNWIND) ^^^
                     return {};
                 }
             }

stl/inc/filesystem

@@ -1374,7 +1374,7 @@ namespace filesystem {
         _NODISCARD_FRIEND bool operator>=(const path& _Left, const path& _Right) noexcept {
             return _Left.compare(_Right) >= 0;
         }
-#endif // !_HAS_CXX20
+#endif // ^^^ !_HAS_CXX20 ^^^
 
         _NODISCARD_FRIEND path operator/(const path& _Left, const path& _Right) { // append a pair of paths together
             path _Tmp = _Left;
@@ -2454,7 +2454,7 @@ namespace filesystem {
         _NODISCARD bool operator>=(const directory_entry& _Rhs) const noexcept {
             return _Path >= _Rhs._Path;
         }
-#endif // !_HAS_CXX20
+#endif // ^^^ !_HAS_CXX20 ^^^
 
         // [fs.dir.entry.io], inserter
         template <class _Elem, class _Traits>
@@ -4430,6 +4430,6 @@ _STD_END
 _STL_RESTORE_CLANG_WARNINGS
 #pragma warning(pop)
 #pragma pack(pop)
-#endif // _HAS_CXX17
+#endif // ^^^ _HAS_CXX17 ^^^
 #endif // _STL_COMPILER_PREPROCESSOR
 #endif // _FILESYSTEM_

stl/inc/format

@@ -4137,6 +4137,6 @@ _STL_RESTORE_CLANG_WARNINGS
 #pragma warning(pop)
 #pragma pack(pop)
 
-#endif // defined(__cpp_lib_concepts)
+#endif // ^^^ defined(__cpp_lib_concepts) ^^^
 #endif // _STL_COMPILER_PREPROCESSOR
 #endif // _FORMAT_

stl/inc/forward_list

@@ -1468,7 +1468,7 @@ private:
         if constexpr (!_Alnode_traits::is_always_equal::value) {
             _STL_VERIFY(_Getal() == _Right._Getal(), "forward_list containers incompatible for splice_after");
         }
-#endif // _ITERATOR_DEBUG_LEVEL == 0
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL != 0 ^^^
 
 #if _ITERATOR_DEBUG_LEVEL == 2
         if (this != _STD addressof(_Right)) {
@@ -1497,7 +1497,7 @@ private:
         if constexpr (!_Alnode_traits::is_always_equal::value) {
             _STL_VERIFY(_Getal() == _Right._Getal(), "forward_list containers incompatible for splice_after");
         }
-#endif // _ITERATOR_DEBUG_LEVEL == 0
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL != 0 ^^^
 
         if (_First == _Last) {
             return;

stl/inc/future

@@ -10,7 +10,7 @@
 
 #ifdef _M_CEE_PURE
 #error <future> is not supported when compiling with /clr:pure.
-#endif // _M_CEE_PURE
+#endif // defined(_M_CEE_PURE)
 
 #ifdef _RESUMABLE_FUNCTIONS_SUPPORTED
 #include <experimental/resumable>

stl/inc/iterator

@@ -1635,7 +1635,7 @@ public:
     _NODISCARD constexpr bool operator>=(const checked_array_iterator& _Right) const noexcept {
         return !(*this < _Right);
     }
-#endif // !_HAS_CXX20
+#endif // ^^^ !_HAS_CXX20 ^^^
 
     friend constexpr void _Verify_range(
         const checked_array_iterator& _First, const checked_array_iterator& _Last) noexcept {
@@ -1804,7 +1804,7 @@ public:
     _NODISCARD constexpr bool operator>=(const unchecked_array_iterator& _Right) const noexcept {
         return !(*this < _Right);
     }
-#endif // !_HAS_CXX20
+#endif // ^^^ !_HAS_CXX20 ^^^
 
 #if _ITERATOR_DEBUG_LEVEL != 0
     friend constexpr void _Verify_range(

stl/inc/latch

@@ -10,7 +10,7 @@
 
 #ifdef _M_CEE_PURE
 #error <latch> is not supported when compiling with /clr:pure.
-#endif // _M_CEE_PURE
+#endif // defined(_M_CEE_PURE)
 
 #if !_HAS_CXX20
 _EMIT_STL_WARNING(STL4038, "The contents of <latch> are available only with C++20 or later.");

stl/inc/list

@@ -370,7 +370,7 @@ public:
         }
 #else // ^^^ _ITERATOR_DEBUG_LEVEL == 2 / _ITERATOR_DEBUG_LEVEL != 2 vvv
         (void) _Ptr;
-#endif // _ITERATOR_DEBUG_LEVEL == 2
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL != 2 ^^^
     }
 
     void _Orphan_non_end() noexcept { // orphan iterators except end()
@@ -985,7 +985,7 @@ public:
         return _Result;
 #else // ^^^ _HAS_CXX17 / !_HAS_CXX17 vvv
         (void) _Result;
-#endif // _HAS_CXX17
+#endif // ^^^ !_HAS_CXX17 ^^^
     }
 
     template <class... _Valty>
@@ -996,7 +996,7 @@ public:
         return _Result;
 #else // ^^^ _HAS_CXX17 / !_HAS_CXX17 vvv
         (void) _Result;
-#endif // _HAS_CXX17
+#endif // ^^^ !_HAS_CXX17 ^^^
     }
 
     template <class... _Valty>

stl/inc/memory

@@ -1843,7 +1843,7 @@ private:
 
     template <class _Ty0, class _Alloc, class... _Types>
     friend shared_ptr<_Ty0> allocate_shared(const _Alloc& _Al_arg, _Types&&... _Args);
-#endif // !_HAS_CXX20
+#endif // ^^^ !_HAS_CXX20 ^^^
 
     template <class _Ux>
     void _Set_ptr_rep_and_enable_shared(_Ux* const _Px, _Ref_count_base* const _Rx) noexcept { // take ownership of _Px
@@ -3009,7 +3009,7 @@ public:
     static constexpr bool
         _Must_avoid_expired_conversions_from<_Ty2, decltype(static_cast<const _Ty2*>(static_cast<_Ty*>(nullptr)))> =
             false;
-#endif // _M_CEE_PURE
+#endif // ^^^ !defined(_M_CEE_PURE) ^^^
 
     constexpr weak_ptr() noexcept {}
 

stl/inc/memory_resource

@@ -751,6 +751,6 @@ _STD_END
 _STL_RESTORE_CLANG_WARNINGS
 #pragma warning(pop)
 #pragma pack(pop)
-#endif // _HAS_CXX17
+#endif // ^^^ _HAS_CXX17 ^^^
 #endif // _STL_COMPILER_PREPROCESSOR
 #endif // _MEMORY_RESOURCE_

stl/inc/mutex

@@ -10,7 +10,7 @@
 
 #ifdef _M_CEE_PURE
 #error <mutex> is not supported when compiling with /clr:pure.
-#endif // _M_CEE_PURE
+#endif // defined(_M_CEE_PURE)
 
 #include <__msvc_chrono.hpp>
 #include <cstdlib>
@@ -43,7 +43,7 @@ public:
     _Mutex_base(int _Flags = 0) noexcept {
         _Mtx_init_in_situ(_Mymtx(), _Flags | _Mtx_try);
     }
-#endif // !_ENABLE_CONSTEXPR_MUTEX_CONSTRUCTOR
+#endif // ^^^ !_ENABLE_CONSTEXPR_MUTEX_CONSTRUCTOR ^^^
 
     ~_Mutex_base() noexcept {
         _Mtx_destroy_in_situ(_Mymtx());

stl/inc/new

@@ -102,7 +102,7 @@ _EXPORT_STD inline constexpr size_t hardware_constructive_interference_size = 64
 _EXPORT_STD inline constexpr size_t hardware_destructive_interference_size  = 64;
 #else // ^^^ supported hardware / unsupported hardware vvv
 #error Unsupported architecture
-#endif // hardware
+#endif // ^^^ unsupported hardware ^^^
 
 #endif // _HAS_CXX17
 

stl/inc/numbers

@@ -144,6 +144,6 @@ _STD_END
 _STL_RESTORE_CLANG_WARNINGS
 #pragma warning(pop)
 #pragma pack(pop)
-#endif // _HAS_CXX20
+#endif // ^^^ _HAS_CXX20 ^^^
 #endif // _STL_COMPILER_PREPROCESSOR
 #endif // _NUMBERS_

stl/inc/numeric

@@ -35,7 +35,7 @@ _NODISCARD _CONSTEXPR20 _Ty accumulate(const _InIt _First, const _InIt _Last, _T
         _Val = _Reduce_op(_STD move(_Val), *_UFirst);
 #else // ^^^ _HAS_CXX20 / !_HAS_CXX20 vvv
         _Val = _Reduce_op(_Val, *_UFirst);
-#endif // _HAS_CXX20
+#endif // ^^^ !_HAS_CXX20 ^^^
     }
     return _Val;
 }
@@ -68,7 +68,7 @@ _Ty _Reduce_plus_arithmetic_ranges(_InIt _First, const _InIt _Last, _Ty _Val) {
 #else // ^^^ _STD_VECTORIZE_WITH_FLOAT_CONTROL / !_STD_VECTORIZE_WITH_FLOAT_CONTROL vvv
 template <class _InIt, class _Ty, class _BinOp>
 inline constexpr bool _Plus_on_arithmetic_ranges_reduction_v = false;
-#endif // _STD_VECTORIZE_WITH_FLOAT_CONTROL
+#endif // ^^^ !_STD_VECTORIZE_WITH_FLOAT_CONTROL ^^^
 
 _EXPORT_STD template <class _InIt, class _Ty, class _BinOp>
 _NODISCARD _CONSTEXPR20 _Ty reduce(const _InIt _First, const _InIt _Last, _Ty _Val, _BinOp _Reduce_op) {
@@ -137,7 +137,7 @@ _NODISCARD _CONSTEXPR20 _Ty inner_product(
         _Val = _Reduce_op(_STD move(_Val), _Transform_op(*_UFirst1, *_UFirst2)); // Requirement missing from N4950
 #else // ^^^ _HAS_CXX20 / !_HAS_CXX20 vvv
         _Val = _Reduce_op(_Val, _Transform_op(*_UFirst1, *_UFirst2)); // Requirement missing from N4950
-#endif // _HAS_CXX20
+#endif // ^^^ !_HAS_CXX20 ^^^
     }
 
     return _Val;
@@ -171,7 +171,7 @@ _Ty _Transform_reduce_arithmetic_defaults(_InIt1 _First1, const _InIt1 _Last1, _
 #else // ^^^ _STD_VECTORIZE_WITH_FLOAT_CONTROL / !_STD_VECTORIZE_WITH_FLOAT_CONTROL vvv
 template <class _InIt1, class _InIt2, class _Ty, class _BinOp1, class _BinOp2>
 inline constexpr bool _Default_ops_transform_reduce_v = false;
-#endif // _STD_VECTORIZE_WITH_FLOAT_CONTROL
+#endif // ^^^ !_STD_VECTORIZE_WITH_FLOAT_CONTROL ^^^
 
 _EXPORT_STD template <class _InIt1, class _InIt2, class _Ty, class _BinOp1, class _BinOp2>
 _NODISCARD _CONSTEXPR20 _Ty transform_reduce(
@@ -260,7 +260,7 @@ _CONSTEXPR20 _OutIt partial_sum(const _InIt _First, const _InIt _Last, _OutIt _D
             _Val = _Reduce_op(_STD move(_Val), *_UFirst);
 #else // ^^^ _HAS_CXX20 / !_HAS_CXX20 vvv
             _Val      = _Reduce_op(_Val, *_UFirst);
-#endif // _HAS_CXX20
+#endif // ^^^ !_HAS_CXX20 ^^^
         }
     }
 
@@ -484,7 +484,7 @@ _CONSTEXPR20 _OutIt adjacent_difference(const _InIt _First, const _InIt _Last, _
             *++_UDest = _Func(_Tmp, _STD move(_Val));
 #else // ^^^ _HAS_CXX20 / !_HAS_CXX20 vvv
             *++_UDest = _Func(_Tmp, _Val);
-#endif // _HAS_CXX20
+#endif // ^^^ !_HAS_CXX20 ^^^
             _Val = _STD move(_Tmp);
         }
 

stl/inc/optional

@@ -797,7 +797,7 @@ template <class _Ty>
 _NODISCARD constexpr bool operator>=(nullopt_t, const optional<_Ty>& _Right) noexcept {
     return !_Right.has_value();
 }
-#endif // !_HAS_CXX20
+#endif // ^^^ !_HAS_CXX20 ^^^
 
 template <class _Ty>
 using _Enable_if_bool_convertible = enable_if_t<is_convertible_v<_Ty, bool>, int>;
@@ -987,6 +987,6 @@ _STD_END
 _STL_RESTORE_CLANG_WARNINGS
 #pragma warning(pop)
 #pragma pack(pop)
-#endif // _HAS_CXX17
+#endif // ^^^ _HAS_CXX17 ^^^
 #endif // _STL_COMPILER_PREPROCESSOR
 #endif // _OPTIONAL_

stl/inc/ostream

@@ -117,7 +117,7 @@ public:
             const bool _Zero_uncaught_exceptions = !_STD uncaught_exception(); // TRANSITION, ArchivedOS-12000909
 #else // ^^^ _HAS_DEPRECATED_UNCAUGHT_EXCEPTION / !_HAS_DEPRECATED_UNCAUGHT_EXCEPTION vvv
             const bool _Zero_uncaught_exceptions = _STD uncaught_exceptions() == 0;
-#endif // !_HAS_DEPRECATED_UNCAUGHT_EXCEPTION
+#endif // ^^^ !_HAS_DEPRECATED_UNCAUGHT_EXCEPTION ^^^
 
             if (_Zero_uncaught_exceptions) {
                 this->_Myostr._Osfx();
@@ -184,7 +184,7 @@ public:
         _Pfn(*this);
         return *this;
     }
-#endif // _M_CEE_PURE
+#endif // defined(_M_CEE_PURE)
 
     basic_ostream& __CLR_OR_THIS_CALL operator<<(basic_ostream&(__cdecl* _Pfn)(basic_ostream&) ) {
         // call basic_ostream manipulator

stl/inc/print

@@ -165,6 +165,6 @@ _STL_RESTORE_CLANG_WARNINGS
 #pragma warning(pop)
 #pragma pack(pop)
 
-#endif // defined(__cpp_lib_print)
+#endif // ^^^ defined(__cpp_lib_print) ^^^
 #endif // _STL_COMPILER_PREPROCESSOR
 #endif // _PRINT_

stl/inc/queue

@@ -135,9 +135,9 @@ public:
     decltype(auto) emplace(_Valty&&... _Val) {
 #if _HAS_CXX17
         return c.emplace_back(_STD forward<_Valty>(_Val)...);
-#else // ^^^ C++17 or newer / C++14 vvv
+#else // ^^^ _HAS_CXX17 / !_HAS_CXX17 vvv
         c.emplace_back(_STD forward<_Valty>(_Val)...);
-#endif // _HAS_CXX17
+#endif // ^^^ !_HAS_CXX17 ^^^
     }
 
     void pop() noexcept(noexcept(c.pop_front())) /* strengthened */ {

stl/inc/random

@@ -26,9 +26,9 @@ _STL_DISABLE_CLANG_WARNINGS
 
 #ifdef _ALLOW_RANDOM_DISTRIBUTION_CONST_OPERATOR
 #define _DISTRIBUTION_CONST const
-#else // ^^^ _ALLOW_RANDOM_DISTRIBUTION_CONST_OPERATOR / !_ALLOW_RANDOM_DISTRIBUTION_CONST_OPERATOR vvv
+#else
 #define _DISTRIBUTION_CONST
-#endif // _ALLOW_RANDOM_DISTRIBUTION_CONST_OPERATOR
+#endif
 
 _STD_BEGIN
 #define _RNG_PROHIBIT_CHAR(_CheckedType)               \

stl/inc/ranges

@@ -99,7 +99,7 @@ namespace ranges {
         move_constructible<_Ty>
 #else // ^^^ C++23 / C++20 vvv
         copy_constructible<_Ty>
-#endif // C++20
+#endif // ^^^ C++20 ^^^
         && _Destructible_object<_Ty>;
 
     template <class _It>
@@ -5720,7 +5720,7 @@ namespace ranges {
             typename tuple_element_t<_Index, _Tuple>;
             { _STD get<_Index>(__t) } -> convertible_to<const tuple_element_t<_Index, _Tuple>&>;
         };
-#endif // C++20
+#endif // ^^^ C++20 ^^^
 
     template <class _Tuple, size_t _Index>
     concept _Returnable_element = is_reference_v<_Tuple> || move_constructible<tuple_element_t<_Index, _Tuple>>;
@@ -10480,6 +10480,6 @@ _STD_END
 _STL_RESTORE_CLANG_WARNINGS
 #pragma warning(pop)
 #pragma pack(pop)
-#endif // defined(__cpp_lib_ranges)
+#endif // ^^^ defined(__cpp_lib_ranges) ^^^
 #endif // _STL_COMPILER_PREPROCESSOR
 #endif // _RANGES_

stl/inc/regex

@@ -35,23 +35,23 @@ _STL_DISABLE_CLANG_WARNINGS
 
 #ifndef _REGEX_MAX_COMPLEXITY_COUNT
 #define _REGEX_MAX_COMPLEXITY_COUNT 10000000L // set to 0 to disable
-#endif // _REGEX_MAX_COMPLEXITY_COUNT
+#endif // !defined(_REGEX_MAX_COMPLEXITY_COUNT)
 
 #ifndef _REGEX_MAX_STACK_COUNT
 #ifdef _WIN64
 #define _REGEX_MAX_STACK_COUNT 600L // set to 0 to disable
-#else // _WIN64
+#else // ^^^ defined(_WIN64) / !defined(_WIN64) vvv
 #define _REGEX_MAX_STACK_COUNT 1000L // set to 0 to disable
-#endif // _WIN64
-#endif // _REGEX_MAX_STACK_COUNT
+#endif // ^^^ !defined(_WIN64) ^^^
+#endif // !defined(_REGEX_MAX_STACK_COUNT)
 
 #ifndef _ENHANCED_REGEX_VISUALIZER
 #ifdef _DEBUG
 #define _ENHANCED_REGEX_VISUALIZER 1
-#else // _DEBUG
+#else // ^^^ defined(_DEBUG) / !defined(_DEBUG) vvv
 #define _ENHANCED_REGEX_VISUALIZER 0
-#endif // _DEBUG
-#endif // _ENHANCED_REGEX_VISUALIZER
+#endif // ^^^ !defined(_DEBUG) ^^^
+#endif // !defined(_ENHANCED_REGEX_VISUALIZER)
 
 _STD_BEGIN
 
@@ -761,7 +761,7 @@ template <class _BidIt>
 _NODISCARD bool operator>=(const sub_match<_BidIt>& _Left, const sub_match<_BidIt>& _Right) {
     return !(_Left < _Right);
 }
-#endif // !_HAS_CXX20
+#endif // ^^^ !_HAS_CXX20 ^^^
 
 _EXPORT_STD template <class _BidIt>
 _NODISCARD bool operator==(const sub_match<_BidIt>& _Left, const _Iter_value_t<_BidIt>* _Right) {
@@ -828,7 +828,7 @@ template <class _BidIt>
 _NODISCARD bool operator>=(const sub_match<_BidIt>& _Left, const _Iter_value_t<_BidIt>* _Right) {
     return !(_Left < _Right);
 }
-#endif // !_HAS_CXX20
+#endif // ^^^ !_HAS_CXX20 ^^^
 
 _EXPORT_STD template <class _BidIt>
 _NODISCARD bool operator==(const sub_match<_BidIt>& _Left, const _Iter_value_t<_BidIt>& _Right) {
@@ -895,7 +895,7 @@ template <class _BidIt>
 _NODISCARD bool operator>=(const sub_match<_BidIt>& _Left, const _Iter_value_t<_BidIt>& _Right) {
     return !(_Left < _Right);
 }
-#endif // !_HAS_CXX20
+#endif // ^^^ !_HAS_CXX20 ^^^
 
 _EXPORT_STD template <class _BidIt, class _Traits, class _Alloc>
 _NODISCARD bool operator==(
@@ -975,7 +975,7 @@ _NODISCARD bool operator>=(
     const sub_match<_BidIt>& _Left, const basic_string<_Iter_value_t<_BidIt>, _Traits, _Alloc>& _Right) {
     return !(_Left < _Right);
 }
-#endif // !_HAS_CXX20
+#endif // ^^^ !_HAS_CXX20 ^^^
 
 _EXPORT_STD template <class _Elem, class _Traits, class _BidIt>
 basic_ostream<_Elem, _Traits>& operator<<(basic_ostream<_Elem, _Traits>& _Ostr, const sub_match<_BidIt>& _Match) {

stl/inc/source_location

@@ -65,6 +65,6 @@ _STD_END
 _STL_RESTORE_CLANG_WARNINGS
 #pragma warning(pop)
 #pragma pack(pop)
-#endif // _HAS_CXX20
+#endif // ^^^ _HAS_CXX20 ^^^
 #endif // _STL_COMPILER_PREPROCESSOR
 #endif // _SOURCE_LOCATION_

stl/inc/span

@@ -598,7 +598,7 @@ public:
         return {_Mydata, _Mydata, _Mydata + _Mysize};
 #else // ^^^ _ITERATOR_DEBUG_LEVEL >= 1 / _ITERATOR_DEBUG_LEVEL == 0 vvv
         return {_Mydata};
-#endif // _ITERATOR_DEBUG_LEVEL
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL == 0 ^^^
     }
 
     _NODISCARD constexpr iterator end() const noexcept {
@@ -607,7 +607,7 @@ public:
         return {_End, _Mydata, _End};
 #else // ^^^ _ITERATOR_DEBUG_LEVEL >= 1 / _ITERATOR_DEBUG_LEVEL == 0 vvv
         return {_End};
-#endif // _ITERATOR_DEBUG_LEVEL
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL == 0 ^^^
     }
 
 #if _HAS_CXX23 && defined(__cpp_lib_concepts)
@@ -695,6 +695,6 @@ _STD_END
 _STL_RESTORE_CLANG_WARNINGS
 #pragma warning(pop)
 #pragma pack(pop)
-#endif // _HAS_CXX20
+#endif // ^^^ _HAS_CXX20 ^^^
 #endif // _STL_COMPILER_PREPROCESSOR
 #endif // _SPAN_

stl/inc/spanstream

@@ -401,6 +401,6 @@ _STD_END
 _STL_RESTORE_CLANG_WARNINGS
 #pragma warning(pop)
 #pragma pack(pop)
-#endif // _HAS_CXX23
+#endif // ^^^ _HAS_CXX23 ^^^
 #endif // _STL_COMPILER_PREPROCESSOR
 #endif // _SPANSTREAM_

stl/inc/sstream

@@ -150,7 +150,7 @@ public:
     _NODISCARD _Mystr str() const&
 #else
     _NODISCARD _Mystr str() const
-#endif // _HAS_CXX20
+#endif
     {
         _Mystr _Result(_Al);
         const auto _View = _Get_buffer_view();
@@ -620,7 +620,7 @@ public:
     _NODISCARD _Mystr str() const&
 #else
     _NODISCARD _Mystr str() const
-#endif // _HAS_CXX20
+#endif
     {
         return _Stringbuffer.str();
     }
@@ -740,7 +740,7 @@ public:
     _NODISCARD _Mystr str() const&
 #else
     _NODISCARD _Mystr str() const
-#endif // _HAS_CXX20
+#endif
     {
         return _Stringbuffer.str();
     }
@@ -866,7 +866,7 @@ public:
     _NODISCARD _Mystr str() const&
 #else
     _NODISCARD _Mystr str() const
-#endif // _HAS_CXX20
+#endif
     {
         return _Stringbuffer.str();
     }

stl/inc/stack

@@ -125,9 +125,9 @@ public:
     decltype(auto) emplace(_Valty&&... _Val) {
 #if _HAS_CXX17
         return c.emplace_back(_STD forward<_Valty>(_Val)...);
-#else // ^^^ C++17 or newer / C++14 vvv
+#else // ^^^ _HAS_CXX17 / !_HAS_CXX17 vvv
         c.emplace_back(_STD forward<_Valty>(_Val)...);
-#endif // _HAS_CXX17
+#endif // ^^^ !_HAS_CXX17 ^^^
     }
 
     void pop() noexcept(noexcept(c.pop_back())) /* strengthened */ {

stl/inc/stop_token

@@ -392,6 +392,6 @@ _STD_END
 _STL_RESTORE_CLANG_WARNINGS
 #pragma warning(pop)
 #pragma pack(pop)
-#endif // _HAS_CXX20
+#endif // ^^^ _HAS_CXX20 ^^^
 #endif // _STL_COMPILER_PREPROCESSOR
 #endif // _STOP_TOKEN_

stl/inc/string

@@ -444,7 +444,7 @@ _NODISCARD _Elem* _UIntegral_to_buff(_Elem* _RNext, _UTy _UVal) {
 
 #ifdef _WIN64
     auto _UVal_trunc = _UVal;
-#else // ^^^ _WIN64 / !_WIN64 vvv
+#else // ^^^ defined(_WIN64) / !defined(_WIN64) vvv
 
     constexpr bool _Big_uty = sizeof(_UTy) > 4;
     if constexpr (_Big_uty) { // For 64-bit numbers, work in chunks to avoid 64-bit divisions.
@@ -460,7 +460,7 @@ _NODISCARD _Elem* _UIntegral_to_buff(_Elem* _RNext, _UTy _UVal) {
     }
 
     auto _UVal_trunc = static_cast<unsigned long>(_UVal);
-#endif // _WIN64
+#endif // ^^^ !defined(_WIN64) ^^^
 
     do {
         *--_RNext = static_cast<_Elem>('0' + _UVal_trunc % 10);

stl/inc/string_view

@@ -12,6 +12,6 @@
 _EMIT_STL_WARNING(STL4038, "The contents of <string_view> are available only with C++17 or later.");
 #else // ^^^ !_HAS_CXX17 / _HAS_CXX17 vvv
 #include <xstring>
-#endif // _HAS_CXX17
+#endif // ^^^ _HAS_CXX17 ^^^
 #endif // _STL_COMPILER_PREPROCESSOR
 #endif // _STRING_VIEW_

stl/inc/syncstream

@@ -380,6 +380,6 @@ _STD_END
 _STL_RESTORE_CLANG_WARNINGS
 #pragma warning(pop)
 #pragma pack(pop)
-#endif // _HAS_CXX20
+#endif // ^^^ _HAS_CXX20 ^^^
 #endif // _STL_COMPILER_PREPROCESSOR
 #endif // _SYNCSTREAM_

stl/inc/system_error

@@ -15,7 +15,7 @@
 #include <xerrc.h>
 #ifndef _M_CEE_PURE
 #include <atomic>
-#endif // _M_CEE_PURE
+#endif // !defined(_M_CEE_PURE)
 
 #if _HAS_CXX20
 #include <compare>
@@ -410,7 +410,7 @@ _NODISCARD inline bool operator!=(const error_condition& _Left, const error_cond
     return !(_Left == _Right);
 }
 #endif // !_HAS_CXX20
-#endif // _STL_OPTIMIZE_SYSTEM_ERROR_OPERATORS
+#endif // ^^^ !_STL_OPTIMIZE_SYSTEM_ERROR_OPERATORS ^^^
 
 _NODISCARD inline error_condition error_category::default_error_condition(int _Errval) const noexcept {
     // make error_condition for error code

stl/inc/thread

@@ -231,7 +231,7 @@ private:
     friend strong_ordering operator<=>(thread::id _Left, thread::id _Right) noexcept;
 #else // ^^^ _HAS_CXX20 / !_HAS_CXX20 vvv
     friend bool operator<(thread::id _Left, thread::id _Right) noexcept;
-#endif // !_HAS_CXX20
+#endif // ^^^ !_HAS_CXX20 ^^^
     template <class _Ch, class _Tr>
     friend basic_ostream<_Ch, _Tr>& operator<<(basic_ostream<_Ch, _Tr>& _Str, thread::id _Id);
     friend hash<thread::id>;
@@ -277,7 +277,7 @@ _NODISCARD inline bool operator>(thread::id _Left, thread::id _Right) noexcept {
 _NODISCARD inline bool operator>=(thread::id _Left, thread::id _Right) noexcept {
     return !(_Left < _Right);
 }
-#endif // !_HAS_CXX20
+#endif // ^^^ !_HAS_CXX20 ^^^
 
 _EXPORT_STD template <class _Ch, class _Tr>
 basic_ostream<_Ch, _Tr>& operator<<(basic_ostream<_Ch, _Tr>& _Str, thread::id _Id) {

stl/inc/tuple

@@ -1044,7 +1044,7 @@ struct _Tuple_cat2<_Ty, index_sequence<_Kx...>, index_sequence<_Ix...>, _Ix_next
 template <_Tuple_like... _Tuples>
 #else // ^^^ C++23 / C++20 vvv
 template <class... _Tuples>
-#endif // C++20
+#endif // ^^^ C++20 ^^^
 using _Tuple_cat1 = _Tuple_cat2<tuple<_Tuples&&...>, index_sequence<>, index_sequence<>, 0,
     make_index_sequence<tuple_size_v<_Remove_cvref_t<_Tuples>>>...>;
 
@@ -1057,7 +1057,7 @@ constexpr _Ret _Tuple_cat(index_sequence<_Kx...>, index_sequence<_Ix...>, _Ty _A
 _EXPORT_STD template <_Tuple_like... _Tuples>
 #else // ^^^ C++23 / C++20 vvv
 _EXPORT_STD template <class... _Tuples>
-#endif // C++20
+#endif // ^^^ C++20 ^^^
 _NODISCARD constexpr typename _Tuple_cat1<_Tuples...>::_Ret tuple_cat(_Tuples&&... _Tpls) { // concatenate tuples
     using _Cat1   = _Tuple_cat1<_Tuples...>;
     using _Ret    = typename _Cat1::_Ret;
@@ -1071,7 +1071,7 @@ _NODISCARD constexpr typename _Tuple_cat1<_Tuples...>::_Ret tuple_cat(_Tuples&&.
 template <class _Callable, _Tuple_like _Tuple, size_t... _Indices>
 #else // ^^^ C++23 / C++20 vvv
 template <class _Callable, class _Tuple, size_t... _Indices>
-#endif // C++20
+#endif // ^^^ C++20 ^^^
 constexpr decltype(auto) _Apply_impl(_Callable&& _Obj, _Tuple&& _Tpl, index_sequence<_Indices...>) noexcept(
     noexcept(_STD invoke(_STD forward<_Callable>(_Obj), _STD get<_Indices>(_STD forward<_Tuple>(_Tpl))...))) {
     return _STD invoke(_STD forward<_Callable>(_Obj), _STD get<_Indices>(_STD forward<_Tuple>(_Tpl))...);
@@ -1081,7 +1081,7 @@ constexpr decltype(auto) _Apply_impl(_Callable&& _Obj, _Tuple&& _Tpl, index_sequ
 _EXPORT_STD template <class _Callable, _Tuple_like _Tuple>
 #else // ^^^ C++23 / C++20 vvv
 _EXPORT_STD template <class _Callable, class _Tuple>
-#endif // C++20
+#endif // ^^^ C++20 ^^^
 constexpr decltype(auto) apply(_Callable&& _Obj, _Tuple&& _Tpl) noexcept(
     noexcept(_Apply_impl(_STD forward<_Callable>(_Obj), _STD forward<_Tuple>(_Tpl),
         make_index_sequence<tuple_size_v<remove_reference_t<_Tuple>>>{}))) {
@@ -1093,7 +1093,7 @@ constexpr decltype(auto) apply(_Callable&& _Obj, _Tuple&& _Tpl) noexcept(
 template <class _Ty, _Tuple_like _Tuple, size_t... _Indices>
 #else // ^^^ C++23 / C++20 vvv
 template <class _Ty, class _Tuple, size_t... _Indices>
-#endif // C++20
+#endif // ^^^ C++20 ^^^
 constexpr _Ty _Make_from_tuple_impl(_Tuple&& _Tpl, index_sequence<_Indices...>) noexcept(
     is_nothrow_constructible_v<_Ty, decltype(_STD get<_Indices>(_STD forward<_Tuple>(_Tpl)))...>) {
     // construct _Ty from the elements of _Tpl
@@ -1106,7 +1106,7 @@ constexpr _Ty _Make_from_tuple_impl(_Tuple&& _Tpl, index_sequence<_Indices...>)
 _EXPORT_STD template <class _Ty, _Tuple_like _Tuple>
 #else // ^^^ C++23 / C++20 vvv
 _EXPORT_STD template <class _Ty, class _Tuple>
-#endif // C++20
+#endif // ^^^ C++20 ^^^
 _NODISCARD constexpr _Ty make_from_tuple(_Tuple&& _Tpl) noexcept(noexcept(_Make_from_tuple_impl<_Ty>(
     _STD forward<_Tuple>(_Tpl), make_index_sequence<tuple_size_v<remove_reference_t<_Tuple>>>{}))) /* strengthened */ {
     // construct _Ty from the elements of _Tpl

stl/inc/type_traits

@@ -377,31 +377,29 @@ _INLINE_VAR constexpr bool is_compound_v = !is_fundamental_v<_Ty>;
 
 #ifdef _M_CEE
 #define _EMIT_CLRCALL(FUNC, OPT1, OPT2, OPT3) FUNC(__clrcall, OPT1, OPT2, OPT3)
-#else // ^^^ defined(_M_CEE) / !defined(_M_CEE) vvv
+#else // ^^^ __clrcall supported / __clrcall not supported vvv
 #define _EMIT_CLRCALL(FUNC, OPT1, OPT2, OPT3)
-#endif // ^^^ !defined(_M_CEE) ^^^
+#endif // ^^^ __clrcall not supported ^^^
 
 #if defined(_M_IX86) && !defined(_M_CEE)
 #define _EMIT_FASTCALL(FUNC, OPT1, OPT2, OPT3) FUNC(__fastcall, OPT1, OPT2, OPT3)
-
-#else // defined(_M_IX86) && !defined(_M_CEE)
+#else // ^^^ __fastcall supported / __fastcall not supported vvv
 #define _EMIT_FASTCALL(FUNC, OPT1, OPT2, OPT3)
-#endif // defined(_M_IX86) && !defined(_M_CEE)
+#endif // ^^^ __fastcall not supported ^^^
 
 #ifdef _M_IX86
 #define _EMIT_STDCALL(FUNC, OPT1, OPT2, OPT3)  FUNC(__stdcall, OPT1, OPT2, OPT3)
 #define _EMIT_THISCALL(FUNC, OPT1, OPT2, OPT3) FUNC(__thiscall, OPT1, OPT2, OPT3)
-#else // ^^^ defined(_M_IX86) / !defined(_M_IX86) vvv
+#else // ^^^ __stdcall and __thiscall supported / __stdcall and __thiscall not supported vvv
 #define _EMIT_STDCALL(FUNC, OPT1, OPT2, OPT3)
 #define _EMIT_THISCALL(FUNC, OPT1, OPT2, OPT3)
-#endif // ^^^ !defined(_M_IX86) ^^^
+#endif // ^^^ __stdcall and __thiscall not supported ^^^
 
 #if ((defined(_M_IX86) && _M_IX86_FP >= 2) || defined(_M_X64)) && !defined(_M_CEE)
 #define _EMIT_VECTORCALL(FUNC, OPT1, OPT2, OPT3) FUNC(__vectorcall, OPT1, OPT2, OPT3)
-
-#else // defined(_M_IX86) && _M_IX86_FP >= 2 etc.
+#else // ^^^ __vectorcall supported / __vectorcall not supported vvv
 #define _EMIT_VECTORCALL(FUNC, OPT1, OPT2, OPT3)
-#endif // defined(_M_IX86) && _M_IX86_FP >= 2 etc.
+#endif // ^^^ __vectorcall not supported ^^^
 
 #define _NON_MEMBER_CALL(FUNC, CV_OPT, REF_OPT, NOEXCEPT_OPT) \
     _EMIT_CDECL(FUNC, CV_OPT, REF_OPT, NOEXCEPT_OPT)          \
@@ -803,7 +801,7 @@ struct _Is_assignable_no_precondition_check : bool_constant<__is_assignable_no_p
 #else // ^^^ Use intrinsic / intrinsic not supported vvv
 template <class _To, class _From>
 using _Is_assignable_no_precondition_check = is_assignable<_To, _From>;
-#endif // defined(_IS_ASSIGNABLE_NOCHECK_SUPPORTED) && !defined(__CUDACC__)
+#endif // ^^^ intrinsic not supported ^^^
 
 _EXPORT_STD template <class _Ty>
 struct is_copy_assignable
@@ -830,7 +828,7 @@ using _Is_copy_assignable_no_precondition_check = is_copy_assignable<_Ty>;
 
 template <class _Ty>
 _INLINE_VAR constexpr bool _Is_copy_assignable_unchecked_v = is_copy_assignable_v<_Ty>;
-#endif // defined(_IS_ASSIGNABLE_NOCHECK_SUPPORTED) && !defined(__CUDACC__)
+#endif // ^^^ intrinsic not supported ^^^
 
 _EXPORT_STD template <class _Ty>
 struct is_move_assignable : bool_constant<__is_assignable(add_lvalue_reference_t<_Ty>, _Ty)> {
@@ -854,7 +852,7 @@ using _Is_move_assignable_no_precondition_check = is_move_assignable<_Ty>;
 
 template <class _Ty>
 _INLINE_VAR constexpr bool _Is_move_assignable_unchecked_v = is_move_assignable_v<_Ty>;
-#endif // defined(_IS_ASSIGNABLE_NOCHECK_SUPPORTED) && !defined(__CUDACC__)
+#endif // ^^^ intrinsic not supported ^^^
 
 _EXPORT_STD template <class _Ty>
 struct is_destructible : bool_constant<__is_destructible(_Ty)> {
@@ -1164,7 +1162,7 @@ struct _Aligned<_Len, _Align, double, false> {
     struct type {
         alignas(_Align) char _Space[_Len];
     };
-#else // ^^^ _ENABLE_EXTENDED_ALIGNED_STORAGE / !_ENABLE_EXTENDED_ALIGNED_STORAGE vvv
+#else // ^^^ defined(_ENABLE_EXTENDED_ALIGNED_STORAGE) / !defined(_ENABLE_EXTENDED_ALIGNED_STORAGE) vvv
 #ifndef _DISABLE_EXTENDED_ALIGNED_STORAGE
     static_assert(_Always_false<_Aligned>,
         "You've instantiated std::aligned_storage<Len, Align> with an extended alignment (in other "
@@ -1175,9 +1173,9 @@ struct _Aligned<_Len, _Align, double, false> {
         "To suppress this error, please define either "
         "(1) _ENABLE_EXTENDED_ALIGNED_STORAGE to confirm that you want a type with an extended alignment, or "
         "(2) _DISABLE_EXTENDED_ALIGNED_STORAGE to get the old non-conforming behavior.");
-#endif // !_DISABLE_EXTENDED_ALIGNED_STORAGE
+#endif // ^^^ !defined(_DISABLE_EXTENDED_ALIGNED_STORAGE) ^^^
     using type = _Align_type<max_align_t, _Len>;
-#endif // _ENABLE_EXTENDED_ALIGNED_STORAGE
+#endif // ^^^ !defined(_ENABLE_EXTENDED_ALIGNED_STORAGE) ^^^
 };
 
 template <size_t _Len, size_t _Align>
@@ -1323,10 +1321,10 @@ struct _Const_lvalue_cond_oper<_Ty1, _Ty2, void_t<_Conditional_type<const _Ty1&,
 
 template <class _Ty1, class _Ty2, class = void>
 struct _Decayed_cond_oper : _Const_lvalue_cond_oper<_Ty1, _Ty2> {};
-#else // ^^^ >= C++20 / <= C++17 vvv
+#else // ^^^ _HAS_CXX20 / !_HAS_CXX20 vvv
 template <class _Ty1, class _Ty2, class = void>
 struct _Decayed_cond_oper {};
-#endif // _HAS_CXX20
+#endif // ^^^ !_HAS_CXX20 ^^^
 
 template <class _Ty1, class _Ty2>
 struct _Decayed_cond_oper<_Ty1, _Ty2, void_t<_Conditional_type<_Ty1, _Ty2>>> {
@@ -2126,7 +2124,7 @@ struct _Is_nothrow_swappable;
 _EXPORT_STD template <class _Ty, enable_if_t<is_move_constructible_v<_Ty> && is_move_assignable_v<_Ty>, int> = 0>
 #else // ^^^ _HAS_CXX17 / !_HAS_CXX17 vvv
 template <class _Ty, int _Enabled = 0>
-#endif // _HAS_CXX17
+#endif // ^^^ !_HAS_CXX17 ^^^
 _CONSTEXPR20 void swap(_Ty&, _Ty&) noexcept(is_nothrow_move_constructible_v<_Ty>&& is_nothrow_move_assignable_v<_Ty>);
 
 _EXPORT_STD template <class _Ty, size_t _Size, enable_if_t<_Is_swappable<_Ty>::value, int> = 0>

stl/inc/typeinfo

@@ -61,7 +61,7 @@ class __non_rtti_object : public bad_typeid { // report a non-RTTI object
 public:
     __non_rtti_object(const char* _Message) : bad_typeid(_Message) {}
 };
-#endif // !_HAS_EXCEPTIONS
+#endif // ^^^ !_HAS_EXCEPTIONS ^^^
 
 [[noreturn]] inline void _Throw_bad_cast() {
     _THROW(bad_cast{});

stl/inc/use_ansi.h

@@ -24,23 +24,22 @@
 #ifdef _DEBUG
 #define _DEBUG_AFFIX "d"
 #define _IDL_DEFAULT 2
-#else
+#else // ^^^ defined(_DEBUG) / !defined(_DEBUG) vvv
 #define _DEBUG_AFFIX ""
 #define _IDL_DEFAULT 0
-#endif
+#endif // ^^^ !defined(_DEBUG) ^^^
 
 #if defined(_DLL) && !defined(_STATIC_CPPLIB)
 #define _LIB_STEM "msvcprt"
-#else
+#else // ^^^ defined(_DLL) && !defined(_STATIC_CPPLIB) / !defined(_DLL) || defined(_STATIC_CPPLIB) vvv
 #define _LIB_STEM "libcpmt"
 
 #if _ITERATOR_DEBUG_LEVEL != _IDL_DEFAULT
 #define _IDL_AFFIX _STRINGIZE(_ITERATOR_DEBUG_LEVEL)
-#endif
-#endif
+#endif // _ITERATOR_DEBUG_LEVEL != _IDL_DEFAULT
+#endif // ^^^ !defined(_DLL) || defined(_STATIC_CPPLIB) ^^^
 
-#ifdef _IDL_AFFIX
-#else
+#ifndef _IDL_AFFIX
 #define _IDL_AFFIX ""
 #endif
 
@@ -51,8 +50,8 @@
 #undef _IDL_DEFAULT
 #undef _LIB_STEM
 
-#endif // _M_CEE_PURE
+#endif // !defined(_M_CEE_PURE)
 
-#endif // _CRT_NOPRAGMA_LIBS
+#endif // !defined(_CRT_NOPRAGMA_LIBS)
 
 #endif // _USE_ANSI_CPP

stl/inc/utility

@@ -123,7 +123,7 @@ _CONSTEXPR20 void swap(_Ty (&_Left)[_Size], _Ty (&_Right)[_Size]) noexcept(_Is_n
 _EXPORT_STD template <class _Ty, enable_if_t<is_move_constructible_v<_Ty> && is_move_assignable_v<_Ty>, int> /* = 0 */>
 #else // ^^^ _HAS_CXX17 / !_HAS_CXX17 vvv
 template <class _Ty, int _Enabled /* = 0 */>
-#endif // _HAS_CXX17
+#endif // ^^^ !_HAS_CXX17 ^^^
 _CONSTEXPR20 void swap(_Ty& _Left, _Ty& _Right) noexcept(
     is_nothrow_move_constructible_v<_Ty>&& is_nothrow_move_assignable_v<_Ty>) {
     _Ty _Tmp = _STD move(_Left);

stl/inc/variant

@@ -1679,7 +1679,7 @@ _NODISCARD constexpr bool operator<=(monostate, monostate) noexcept {
 _NODISCARD constexpr bool operator>=(monostate, monostate) noexcept {
     return true;
 }
-#endif // !_HAS_CXX20
+#endif // ^^^ !_HAS_CXX20 ^^^
 
 _EXPORT_STD template <class... _Types,
     enable_if_t<conjunction_v<is_move_constructible<_Types>..., is_swappable<_Types>...>, int> = 0>
@@ -1732,6 +1732,6 @@ _STD_END
 _STL_RESTORE_CLANG_WARNINGS
 #pragma warning(pop)
 #pragma pack(pop)
-#endif // _HAS_CXX17
+#endif // ^^^ _HAS_CXX17 ^^^
 #endif // _STL_COMPILER_PREPROCESSOR
 #endif // _VARIANT_

stl/inc/vector

@@ -117,7 +117,7 @@ public:
         if (_Off > 0) {
             _STL_VERIFY(_Off <= _Mycont->_Mylast - _Ptr, "cannot seek vector iterator after end");
         }
-#endif // _ITERATOR_DEBUG_LEVEL == 0
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL != 0 ^^^
     }
 
     _CONSTEXPR20 _Vector_const_iterator& operator+=(const difference_type _Off) noexcept {
@@ -188,7 +188,7 @@ public:
     _NODISCARD bool operator>=(const _Vector_const_iterator& _Right) const noexcept {
         return !(*this < _Right);
     }
-#endif // !_HAS_CXX20
+#endif // ^^^ !_HAS_CXX20 ^^^
 
     _CONSTEXPR20 void _Compat(const _Vector_const_iterator& _Right) const noexcept {
         // test for compatible iterator pair
@@ -196,7 +196,7 @@ public:
         (void) _Right;
 #else // ^^^ _ITERATOR_DEBUG_LEVEL == 0 / _ITERATOR_DEBUG_LEVEL != 0 vvv
         _STL_VERIFY(this->_Getcont() == _Right._Getcont(), "vector iterators incompatible");
-#endif // _ITERATOR_DEBUG_LEVEL == 0
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL != 0 ^^^
     }
 
 #if _ITERATOR_DEBUG_LEVEL != 0
@@ -594,7 +594,7 @@ private:
 #define _ASAN_VECTOR_CREATE_GUARD
 #define _ASAN_VECTOR_EXTEND_GUARD(n)
 #define _ASAN_VECTOR_RELEASE_GUARD
-#endif // !_INSERT_VECTOR_ANNOTATION
+#endif // ^^^ !_INSERT_VECTOR_ANNOTATION ^^^
 
     using _Scary_val = _Vector_val<conditional_t<_Is_simple_alloc_v<_Alty>, _Simple_types<_Ty>,
         _Vec_iter_types<_Ty, size_type, difference_type, pointer, const_pointer>>>;
@@ -864,7 +864,7 @@ public:
         return _Result;
 #else // ^^^ _HAS_CXX17 / !_HAS_CXX17 vvv
         (void) _Result;
-#endif // _HAS_CXX17
+#endif // ^^^ !_HAS_CXX17 ^^^
     }
 
     _CONSTEXPR20 void push_back(const _Ty& _Val) { // insert element at end, provide strong guarantee
@@ -2183,7 +2183,7 @@ private:
     }
 #else // ^^^ _ITERATOR_DEBUG_LEVEL == 2 / _ITERATOR_DEBUG_LEVEL != 2 vvv
     _CONSTEXPR20 void _Orphan_range(pointer, pointer) const {}
-#endif // _ITERATOR_DEBUG_LEVEL != 2
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL != 2 ^^^
 
     _NODISCARD _CONSTEXPR20 _Alty& _Getal() noexcept {
         return _Mypair._Get_first();
@@ -2636,7 +2636,7 @@ public:
     _NODISCARD bool operator>=(const _Vb_const_iterator& _Right) const noexcept {
         return !(*this < _Right);
     }
-#endif // !_HAS_CXX20
+#endif // ^^^ !_HAS_CXX20 ^^^
 
     _CONSTEXPR20 void _Compat(const _Vb_const_iterator& _Right) const noexcept {
         // test for compatible iterator pair
@@ -2983,7 +2983,7 @@ public:
         this->_Mysize = _STD exchange(_Right._Mysize, size_type{0});
         this->_Swap_proxy_and_iterators(_Right);
 
-#endif // _ITERATOR_DEBUG_LEVEL == 0
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL != 0 ^^^
         return *this;
     }
 
@@ -3050,7 +3050,7 @@ public:
 
         this->_Myvec  = _Right._Myvec;
         this->_Mysize = _Right._Mysize;
-#endif // _ITERATOR_DEBUG_LEVEL == 0
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL != 0 ^^^
 
         return *this;
     }

stl/inc/xbit_ops.h

@@ -30,7 +30,7 @@ _NODISCARD inline unsigned long _Floor_of_log_2(size_t _Value) noexcept { // ret
     _Result = 63;
 #else // ^^^ 64-bit / 32-bit vvv
     _Result = 31;
-#endif // 64 vs. 32-bit
+#endif // ^^^ 32-bit ^^^
 
     while ((size_t{1} << _Result) > _Value) {
         --_Result;
@@ -41,7 +41,7 @@ _NODISCARD inline unsigned long _Floor_of_log_2(size_t _Value) noexcept { // ret
     _BitScanReverse64(&_Result, _Value); // lgtm [cpp/conditionallyuninitializedvariable]
 #else // ^^^ 64-bit / 32-bit vvv
     _BitScanReverse(&_Result, _Value); // lgtm [cpp/conditionallyuninitializedvariable]
-#endif // 64 vs. 32-bit
+#endif // ^^^ 32-bit ^^^
 #endif // ^^^ !defined(_M_CEE_PURE) ^^^
 
     return _Result;

stl/inc/xhash

@@ -1017,7 +1017,7 @@ private:
         _Mylist& _List;
         const _Nodeptr _Predecessor;
         _Nodeptr _Next;
-#endif
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL != 2 ^^^
     };
 
     _Nodeptr _Unchecked_erase(_Nodeptr _First, const _Nodeptr _Last) noexcept(_Nothrow_hash<_Traits, key_type>) {

stl/inc/xlocinfo

@@ -227,7 +227,7 @@ public:
     __CLR_OR_THIS_CALL _Locinfo(const char* _Pch = "C")
 #ifndef _M_CEE_PURE
         : _Lock(_LOCK_LOCALE)
-#endif // _M_CEE_PURE
+#endif // !defined(_M_CEE_PURE)
     {
         if (_Pch) {
             _Locinfo_ctor(this, _Pch);
@@ -240,7 +240,7 @@ public:
     __CLR_OR_THIS_CALL _Locinfo(int _Cat, const char* _Pch)
 #ifndef _M_CEE_PURE
         : _Lock(_LOCK_LOCALE)
-#endif // _M_CEE_PURE
+#endif // !defined(_M_CEE_PURE)
     {
         if (_Pch) {
             _Locinfo_ctor(this, _Cat, _Pch);

stl/inc/xmemory

@@ -1261,7 +1261,7 @@ public:
         }
 #else // ^^^ _ITERATOR_DEBUG_LEVEL == 2 / _ITERATOR_DEBUG_LEVEL != 2 vvv
         _Myproxy = _Right._Myproxy;
-#endif // _ITERATOR_DEBUG_LEVEL != 2
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL != 2 ^^^
         return *this;
     }
 
@@ -1295,7 +1295,7 @@ public:
             _Myproxy = nullptr;
         }
     }
-#endif // _ITERATOR_DEBUG_LEVEL != 2
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL != 2 ^^^
 
     _CONSTEXPR20 const _Container_base12* _Getcont() const noexcept {
         return _Myproxy ? _Myproxy->_Mycont : nullptr;
@@ -1420,7 +1420,7 @@ _CONSTEXPR20 void _Container_base12::_Swap_proxy_and_iterators(_Container_base12
     }
 #else // ^^^ _ITERATOR_DEBUG_LEVEL == 2 / _ITERATOR_DEBUG_LEVEL != 2 vvv
     _Swap_proxy_and_iterators_unlocked(_Right);
-#endif // _ITERATOR_DEBUG_LEVEL != 2
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL != 2 ^^^
 }
 
 #if _ITERATOR_DEBUG_LEVEL == 0

stl/inc/xpolymorphic_allocator.h

@@ -195,9 +195,9 @@ namespace pmr {
 
 #if _HAS_CXX20 && defined(__cpp_lib_byte)
     _EXPORT_STD template <class _Ty = byte>
-#else
+#else // ^^^ _HAS_CXX20 && defined(__cpp_lib_byte) / !_HAS_CXX20 || !defined(__cpp_lib_byte) vvv
     _EXPORT_STD template <class _Ty>
-#endif // _HAS_CXX20 && defined(__cpp_lib_byte)
+#endif // ^^^ !_HAS_CXX20 || !defined(__cpp_lib_byte) ^^^
     class polymorphic_allocator {
     public:
         template <class>

stl/inc/xstring

@@ -918,7 +918,7 @@ private:
         : _Mydata(_Data), _Mysize(_Size), _Myoff(_Off) {}
 #else // ^^^ _ITERATOR_DEBUG_LEVEL >= 1 / _ITERATOR_DEBUG_LEVEL == 0 vvv
     constexpr explicit _String_view_iterator(const pointer _Ptr) noexcept : _Myptr(_Ptr) {}
-#endif // _ITERATOR_DEBUG_LEVEL
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL == 0 ^^^
 
 public:
     _NODISCARD constexpr reference operator*() const noexcept {
@@ -928,7 +928,7 @@ public:
         return _Mydata[_Myoff];
 #else // ^^^ _ITERATOR_DEBUG_LEVEL >= 1 / _ITERATOR_DEBUG_LEVEL == 0 vvv
         return *_Myptr;
-#endif // _ITERATOR_DEBUG_LEVEL
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL == 0 ^^^
     }
 
     _NODISCARD constexpr pointer operator->() const noexcept {
@@ -938,7 +938,7 @@ public:
         return _Mydata + _Myoff;
 #else // ^^^ _ITERATOR_DEBUG_LEVEL >= 1 / _ITERATOR_DEBUG_LEVEL == 0 vvv
         return _Myptr;
-#endif // _ITERATOR_DEBUG_LEVEL
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL == 0 ^^^
     }
 
     constexpr _String_view_iterator& operator++() noexcept {
@@ -948,7 +948,7 @@ public:
         ++_Myoff;
 #else // ^^^ _ITERATOR_DEBUG_LEVEL >= 1 / _ITERATOR_DEBUG_LEVEL == 0 vvv
         ++_Myptr;
-#endif // _ITERATOR_DEBUG_LEVEL
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL == 0 ^^^
         return *this;
     }
 
@@ -965,7 +965,7 @@ public:
         --_Myoff;
 #else // ^^^ _ITERATOR_DEBUG_LEVEL >= 1 / _ITERATOR_DEBUG_LEVEL == 0 vvv
         --_Myptr;
-#endif // _ITERATOR_DEBUG_LEVEL
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL == 0 ^^^
         return *this;
     }
 
@@ -991,7 +991,7 @@ public:
         }
 #else // ^^^ _ITERATOR_DEBUG_LEVEL >= 1 / _ITERATOR_DEBUG_LEVEL == 0 vvv
         (void) _Off;
-#endif // _ITERATOR_DEBUG_LEVEL >= 1
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL == 0 ^^^
     }
 
     constexpr _String_view_iterator& operator+=(const difference_type _Off) noexcept {
@@ -1000,7 +1000,7 @@ public:
         _Myoff += static_cast<size_t>(_Off);
 #else // ^^^ _ITERATOR_DEBUG_LEVEL >= 1 / _ITERATOR_DEBUG_LEVEL == 0 vvv
         _Myptr += _Off;
-#endif // _ITERATOR_DEBUG_LEVEL
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL == 0 ^^^
 
         return *this;
     }
@@ -1035,7 +1035,7 @@ public:
         _Myoff -= static_cast<size_t>(_Off);
 #else // ^^^ _ITERATOR_DEBUG_LEVEL >= 1 / _ITERATOR_DEBUG_LEVEL == 0 vvv
         _Myptr -= _Off;
-#endif // _ITERATOR_DEBUG_LEVEL
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL == 0 ^^^
 
         return *this;
     }
@@ -1053,7 +1053,7 @@ public:
         return static_cast<difference_type>(_Myoff - _Right._Myoff);
 #else // ^^^ _ITERATOR_DEBUG_LEVEL >= 1 / _ITERATOR_DEBUG_LEVEL == 0 vvv
         return _Myptr - _Right._Myptr;
-#endif // _ITERATOR_DEBUG_LEVEL
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL == 0 ^^^
     }
 
     _NODISCARD constexpr reference operator[](const difference_type _Off) const noexcept {
@@ -1067,7 +1067,7 @@ public:
         return _Myoff == _Right._Myoff;
 #else // ^^^ _ITERATOR_DEBUG_LEVEL >= 1 / _ITERATOR_DEBUG_LEVEL == 0 vvv
         return _Myptr == _Right._Myptr;
-#endif // _ITERATOR_DEBUG_LEVEL
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL == 0 ^^^
     }
 
 #if _HAS_CXX20
@@ -1078,7 +1078,7 @@ public:
         return _Myoff <=> _Right._Myoff;
 #else // ^^^ _ITERATOR_DEBUG_LEVEL >= 1 / _ITERATOR_DEBUG_LEVEL == 0 vvv
         return _Myptr <=> _Right._Myptr;
-#endif // _ITERATOR_DEBUG_LEVEL
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL == 0 ^^^
     }
 #else // ^^^ _HAS_CXX20 / !_HAS_CXX20 vvv
     _NODISCARD constexpr bool operator!=(const _String_view_iterator& _Right) const noexcept {
@@ -1092,7 +1092,7 @@ public:
         return _Myoff < _Right._Myoff;
 #else // ^^^ _ITERATOR_DEBUG_LEVEL >= 1 / _ITERATOR_DEBUG_LEVEL == 0 vvv
         return _Myptr < _Right._Myptr;
-#endif // _ITERATOR_DEBUG_LEVEL
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL == 0 ^^^
     }
 
     _NODISCARD constexpr bool operator>(const _String_view_iterator& _Right) const noexcept {
@@ -1123,7 +1123,7 @@ public:
         return _Mydata + _Myoff;
 #else // ^^^ _ITERATOR_DEBUG_LEVEL >= 1 / _ITERATOR_DEBUG_LEVEL == 0 vvv
         return _Myptr;
-#endif // _ITERATOR_DEBUG_LEVEL
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL == 0 ^^^
     }
 
     static constexpr bool _Unwrap_when_unverified = _ITERATOR_DEBUG_LEVEL == 0;
@@ -1133,7 +1133,7 @@ public:
         _Myoff = static_cast<size_t>(_It - _Mydata);
 #else // ^^^ _ITERATOR_DEBUG_LEVEL >= 1 / _ITERATOR_DEBUG_LEVEL == 0 vvv
         _Myptr = _It;
-#endif // _ITERATOR_DEBUG_LEVEL
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL == 0 ^^^
     }
 
 private:
@@ -1143,7 +1143,7 @@ private:
     size_t _Myoff   = 0;
 #else // ^^^ _ITERATOR_DEBUG_LEVEL >= 1 / _ITERATOR_DEBUG_LEVEL == 0 vvv
     pointer _Myptr = nullptr;
-#endif // _ITERATOR_DEBUG_LEVEL
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL == 0 ^^^
 };
 
 #if _HAS_CXX20
@@ -1239,7 +1239,7 @@ public:
         return const_iterator(_Mydata, _Mysize, 0);
 #else // ^^^ _ITERATOR_DEBUG_LEVEL >= 1 / _ITERATOR_DEBUG_LEVEL == 0 vvv
         return const_iterator(_Mydata);
-#endif // _ITERATOR_DEBUG_LEVEL
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL == 0 ^^^
     }
 
     _NODISCARD constexpr const_iterator end() const noexcept {
@@ -1247,7 +1247,7 @@ public:
         return const_iterator(_Mydata, _Mysize, _Mysize);
 #else // ^^^ _ITERATOR_DEBUG_LEVEL >= 1 / _ITERATOR_DEBUG_LEVEL == 0 vvv
         return const_iterator(_Mydata + _Mysize);
-#endif // _ITERATOR_DEBUG_LEVEL
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL == 0 ^^^
     }
 
     _NODISCARD constexpr const_iterator cbegin() const noexcept {
@@ -1934,7 +1934,7 @@ public:
         }
 #else // ^^^ _ITERATOR_DEBUG_LEVEL >= 1 / _ITERATOR_DEBUG_LEVEL == 0 vvv
         (void) _Off;
-#endif // _ITERATOR_DEBUG_LEVEL >= 1
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL == 0 ^^^
     }
 
     _CONSTEXPR20 _String_const_iterator& operator+=(const difference_type _Off) noexcept {
@@ -2016,7 +2016,7 @@ public:
                                                            " point to different string instances)");
 #else // ^^^ _ITERATOR_DEBUG_LEVEL >= 1 / _ITERATOR_DEBUG_LEVEL == 0 vvv
         (void) _Right;
-#endif // _ITERATOR_DEBUG_LEVEL
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL == 0 ^^^
     }
 
 #if _ITERATOR_DEBUG_LEVEL >= 1
@@ -2479,7 +2479,7 @@ private:
 #define _ASAN_STRING_REMOVE(_Str)
 #define _ASAN_STRING_CREATE(_Str)
 #define _ASAN_STRING_MODIFY(_Str, _Old_size, _New_size)
-#endif // !_INSERT_STRING_ANNOTATION
+#endif // ^^^ !_INSERT_STRING_ANNOTATION ^^^
 
 public:
     _CONSTEXPR20
@@ -2666,7 +2666,7 @@ private:
                 _Traits::copy(_My_data._Bx._Buf, _Arg, _Count + 1);
 #else // ^^^ _INSERT_STRING_ANNOTATION / !_INSERT_STRING_ANNOTATION vvv
                 _Traits::copy(_My_data._Bx._Buf, _Arg, _BUF_SIZE);
-#endif // !_INSERT_STRING_ANNOTATION
+#endif // ^^^ !_INSERT_STRING_ANNOTATION ^^^
             }
 
             _Proxy._Release();
@@ -3493,7 +3493,7 @@ public:
         const bool _Check_overlap = _Count <= _Mypair._Myval2._Myres - _Old_size && !_STD is_constant_evaluated();
 #else // ^^^ _HAS_CXX20 / !_HAS_CXX20 vvv
         const bool _Check_overlap = _Count <= _Mypair._Myval2._Myres - _Old_size;
-#endif // _HAS_CXX20
+#endif // ^^^ !_HAS_CXX20 ^^^
 
         if (_Check_overlap) {
             _ASAN_STRING_MODIFY(*this, _Old_size, _Old_size + _Count);

stl/inc/xtr1common

@@ -172,7 +172,7 @@ _INLINE_VAR constexpr bool _Is_any_of_v = // true if and only if _Ty is in _Type
     (is_same_v<_Ty, _Types> || ...);
 #else // ^^^ _HAS_CXX17 / !_HAS_CXX17 vvv
     disjunction_v<is_same<_Ty, _Types>...>;
-#endif // _HAS_CXX17
+#endif // ^^^ !_HAS_CXX17 ^^^
 
 _NODISCARD constexpr bool _Is_constant_evaluated() noexcept { // Internal function for any standard mode
     return __builtin_is_constant_evaluated();

stl/inc/xtree

@@ -213,7 +213,7 @@ public:
         _STL_VERIFY(_Ptrsav != this->_Ptr, "cannot decrement begin map/set iterator");
 #else // ^^^ _ITERATOR_DEBUG_LEVEL == 2 / _ITERATOR_DEBUG_LEVEL != 2 vvv
         _Mybase::operator--();
-#endif // _ITERATOR_DEBUG_LEVEL == 2
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL != 2 ^^^
 
         return *this;
     }
@@ -726,7 +726,7 @@ public:
         }
 #else // ^^^ _ITERATOR_DEBUG_LEVEL == 2 / _ITERATOR_DEBUG_LEVEL != 2 vvv
         (void) _Ptr;
-#endif // _ITERATOR_DEBUG_LEVEL == 2
+#endif // ^^^ _ITERATOR_DEBUG_LEVEL != 2 ^^^
     }
 
     template <class _Alnode>

stl/inc/xutility

@@ -1298,7 +1298,7 @@ using _Guide_key_t =
     remove_const_t<tuple_element_t<0, typename iterator_traits<_Iter>::value_type>>;
 #else // ^^^ C++23 / C++20 vvv
     remove_const_t<typename iterator_traits<_Iter>::value_type::first_type>;
-#endif // C++20
+#endif // ^^^ C++20 ^^^
 
 template <class _Iter>
 using _Guide_val_t =
@@ -1306,7 +1306,7 @@ using _Guide_val_t =
     tuple_element_t<1, typename iterator_traits<_Iter>::value_type>;
 #else // ^^^ C++23 / C++20 vvv
     typename iterator_traits<_Iter>::value_type::second_type;
-#endif // C++20
+#endif // ^^^ C++20 ^^^
 
 template <class _Iter>
 using _Guide_pair_t =
@@ -1316,7 +1316,7 @@ using _Guide_pair_t =
 #else // ^^^ C++23 / C++20 vvv
     pair<add_const_t<typename iterator_traits<_Iter>::value_type::first_type>,
         typename iterator_traits<_Iter>::value_type::second_type>;
-#endif // C++20
+#endif // ^^^ C++20 ^^^
 
 _EXPORT_STD template <class _Ty>
 struct is_execution_policy : false_type {};
@@ -2710,7 +2710,7 @@ namespace ranges {
         {
             return _RANGES begin(static_cast<_CTy&&>(_Val));
         }
-#endif // C++20
+#endif // ^^^ C++20 ^^^
     };
 
     inline namespace _Cpos {
@@ -2740,7 +2740,7 @@ namespace ranges {
         {
             return _RANGES end(static_cast<_CTy&&>(_Val));
         }
-#endif // C++20
+#endif // ^^^ C++20 ^^^
     };
 
     inline namespace _Cpos {
@@ -2907,7 +2907,7 @@ namespace ranges {
         {
             return _RANGES rbegin(static_cast<_CTy&&>(_Val));
         }
-#endif // C++20
+#endif // ^^^ C++20 ^^^
     };
 
     inline namespace _Cpos {
@@ -2937,7 +2937,7 @@ namespace ranges {
         {
             return _RANGES rend(static_cast<_CTy&&>(_Val));
         }
-#endif // C++20
+#endif // ^^^ C++20 ^^^
     };
 
     inline namespace _Cpos {
@@ -3162,7 +3162,7 @@ namespace ranges {
         {
             return _RANGES data(static_cast<_CTy&&>(_Val));
         }
-#endif // C++20
+#endif // ^^^ C++20 ^^^
     };
 
     inline namespace _Cpos {

stl/inc/yvals.h

@@ -15,7 +15,7 @@
 #ifdef _ENFORCE_ONLY_CORE_HEADERS
 _EMIT_STL_ERROR(
     STL1005, "Tried to include a non-core C++ Standard Library header file with _ENFORCE_ONLY_CORE_HEADERS defined.");
-#endif // _ENFORCE_ONLY_CORE_HEADERS
+#endif // defined(_ENFORCE_ONLY_CORE_HEADERS)
 
 #include <crtdbg.h>
 #include <crtdefs.h>
@@ -47,15 +47,15 @@ _STL_DISABLE_CLANG_WARNINGS
 #else
 #define _CRT_MSVCP_CURRENT "msvcp_win.dll"
 #endif
-#else
+#else // ^^^ defined(_CRT_WINDOWS) / !defined(_CRT_WINDOWS) vvv
 // Visual Studio
 #ifdef _DEBUG
 #define _CRT_MSVCP_CURRENT "msvcp140d.dll"
 #else
 #define _CRT_MSVCP_CURRENT "msvcp140.dll"
 #endif
-#endif
-#endif
+#endif // ^^^ !defined(_CRT_WINDOWS) ^^^
+#endif // !defined(_CRT_MSVCP_CURRENT)
 
 #ifdef _ITERATOR_DEBUG_LEVEL // A. _ITERATOR_DEBUG_LEVEL is already defined.
 
@@ -79,7 +79,7 @@ _STL_DISABLE_CLANG_WARNINGS
 #else
 #define _HAS_ITERATOR_DEBUGGING 0
 #endif
-#endif // _HAS_ITERATOR_DEBUGGING
+#endif // ^^^ !defined(_HAS_ITERATOR_DEBUGGING) ^^^
 
 // A3. Inspect _SECURE_SCL.
 #ifdef _SECURE_SCL // A3i. _SECURE_SCL is already defined, validate it.
@@ -111,7 +111,7 @@ _STL_DISABLE_CLANG_WARNINGS
 #else
 #define _HAS_ITERATOR_DEBUGGING 0
 #endif
-#endif // _HAS_ITERATOR_DEBUGGING
+#endif // ^^^ !defined(_HAS_ITERATOR_DEBUGGING) ^^^
 
 // B2. Inspect _SECURE_SCL.
 #ifdef _SECURE_SCL // B2i. _SECURE_SCL is already defined, validate it.
@@ -131,19 +131,19 @@ _STL_DISABLE_CLANG_WARNINGS
 #define _ITERATOR_DEBUG_LEVEL 2
 #elif _SECURE_SCL
 #define _ITERATOR_DEBUG_LEVEL 1
-#else
+#else // ^^^ _SECURE_SCL / !_SECURE_SCL vvv
 #define _ITERATOR_DEBUG_LEVEL 0
-#endif
+#endif // ^^^ !_HAS_ITERATOR_DEBUGGING && !_SECURE_SCL ^^^
 
 #endif // ^^^ !defined(_ITERATOR_DEBUG_LEVEL) ^^^
 
 #ifndef _ALLOW_MSC_VER_MISMATCH
 #pragma detect_mismatch("_MSC_VER", "1900")
-#endif // _ALLOW_MSC_VER_MISMATCH
+#endif // !defined(_ALLOW_MSC_VER_MISMATCH)
 
 #ifndef _ALLOW_ITERATOR_DEBUG_LEVEL_MISMATCH
 #pragma detect_mismatch("_ITERATOR_DEBUG_LEVEL", _STRINGIZE(_ITERATOR_DEBUG_LEVEL))
-#endif // _ALLOW_ITERATOR_DEBUG_LEVEL_MISMATCH
+#endif // !defined(_ALLOW_ITERATOR_DEBUG_LEVEL_MISMATCH)
 
 #ifndef _ALLOW_RUNTIME_LIBRARY_MISMATCH
 #if !defined(_DLL) && !defined(_DEBUG)
@@ -155,7 +155,7 @@ _STL_DISABLE_CLANG_WARNINGS
 #elif defined(_DLL) && defined(_DEBUG)
 #pragma detect_mismatch("RuntimeLibrary", "MDd_DynamicDebug")
 #endif // defined(_DLL) etc.
-#endif // _ALLOW_RUNTIME_LIBRARY_MISMATCH
+#endif // !defined(_ALLOW_RUNTIME_LIBRARY_MISMATCH)
 
 #ifndef _CONTAINER_DEBUG_LEVEL
 #if _ITERATOR_DEBUG_LEVEL == 0
@@ -163,7 +163,7 @@ _STL_DISABLE_CLANG_WARNINGS
 #else // ^^^ _ITERATOR_DEBUG_LEVEL == 0 / _ITERATOR_DEBUG_LEVEL != 0 vvv
 #define _CONTAINER_DEBUG_LEVEL 1
 #endif // _ITERATOR_DEBUG_LEVEL == 0
-#endif // _CONTAINER_DEBUG_LEVEL
+#endif // !defined(_CONTAINER_DEBUG_LEVEL)
 
 #if _ITERATOR_DEBUG_LEVEL != 0 && _CONTAINER_DEBUG_LEVEL == 0
 #error _ITERATOR_DEBUG_LEVEL != 0 must imply _CONTAINER_DEBUG_LEVEL == 1.
@@ -177,7 +177,7 @@ _STL_DISABLE_CLANG_WARNINGS
 #else // ^^^ defined(_DEBUG) / !defined(_DEBUG) vvv
 #define _STL_CRT_SECURE_INVALID_PARAMETER(expr) _CRT_SECURE_INVALID_PARAMETER(expr)
 #endif // ^^^ !defined(_DEBUG) ^^^
-#endif // _STL_CRT_SECURE_INVALID_PARAMETER
+#endif // !defined(_STL_CRT_SECURE_INVALID_PARAMETER)
 
 #define _STL_REPORT_ERROR(mesg)                  \
     do {                                         \
@@ -217,9 +217,9 @@ _STL_DISABLE_CLANG_WARNINGS
 
 #ifdef _ENABLE_STL_INTERNAL_CHECK
 #define _STL_INTERNAL_CHECK(...) _STL_VERIFY(__VA_ARGS__, "STL internal check: " #__VA_ARGS__)
-#else // ^^^ _ENABLE_STL_INTERNAL_CHECK / !_ENABLE_STL_INTERNAL_CHECK vvv
+#else // ^^^ defined(_ENABLE_STL_INTERNAL_CHECK) / !defined(_ENABLE_STL_INTERNAL_CHECK) vvv
 #define _STL_INTERNAL_CHECK(...) _Analysis_assume_(__VA_ARGS__)
-#endif // _ENABLE_STL_INTERNAL_CHECK
+#endif // ^^^ !defined(_ENABLE_STL_INTERNAL_CHECK) ^^^
 
 #ifndef _ENABLE_ATOMIC_REF_ALIGNMENT_CHECK
 #ifdef _DEBUG
@@ -227,7 +227,7 @@ _STL_DISABLE_CLANG_WARNINGS
 #else // ^^^ defined(_DEBUG) / !defined(_DEBUG) vvv
 #define _ENABLE_ATOMIC_REF_ALIGNMENT_CHECK 0
 #endif // ^^^ !defined(_DEBUG) ^^^
-#endif // _ENABLE_ATOMIC_REF_ALIGNMENT_CHECK
+#endif // !defined(_ENABLE_ATOMIC_REF_ALIGNMENT_CHECK)
 
 #if _ENABLE_ATOMIC_REF_ALIGNMENT_CHECK
 #define _ATOMIC_REF_CHECK_ALIGNMENT(cond, mesg) _STL_VERIFY(cond, mesg)
@@ -245,11 +245,11 @@ _EMIT_STL_WARNING(STL4000, "_STATIC_CPPLIB is deprecated and will be REMOVED.");
 #ifdef _M_CEE_MIXED
 #error _STATIC_CPPLIB is not supported while building with /clr
 #endif
-#endif // !_DISABLE_DEPRECATE_STATIC_CPPLIB
+#endif // !defined(_DISABLE_DEPRECATE_STATIC_CPPLIB)
 #ifdef _M_CEE_PURE
 #error _STATIC_CPPLIB cannot be used with /clr:pure (the resulting assembly would not be pure)
 #endif
-#endif // _STATIC_CPPLIB
+#endif // defined(_STATIC_CPPLIB)
 
 #if defined(_M_CEE_PURE) && !defined(_SILENCE_CLR_PURE_DEPRECATION_WARNING)
 _EMIT_STL_WARNING(STL4001, "/clr:pure is deprecated and will be REMOVED.");
@@ -261,7 +261,7 @@ _EMIT_STL_WARNING(STL4001, "/clr:pure is deprecated and will be REMOVED.");
 #else
 #define _MRTIMP2_PURE _MRTIMP2
 #endif
-#endif // _MRTIMP2_PURE
+#endif // !defined(_MRTIMP2_PURE)
 
 #if defined(_DLL) && !defined(_STATIC_CPPLIB) && !defined(_M_CEE_PURE)
 #define _DLL_CPPLIB
@@ -273,17 +273,17 @@ _EMIT_STL_WARNING(STL4001, "/clr:pure is deprecated and will be REMOVED.");
 #else
 #define _CRTIMP2_PURE _CRTIMP2
 #endif
-#endif // _CRTIMP2_PURE
+#endif // !defined(_CRTIMP2_PURE)
 
 #ifndef _CRTIMP2_IMPORT
 #if defined(CRTDLL2) && defined(_CRTBLD)
 #define _CRTIMP2_IMPORT __declspec(dllexport)
 #elif defined(_DLL) && !defined(_STATIC_CPPLIB)
 #define _CRTIMP2_IMPORT __declspec(dllimport)
-#else
+#else // ^^^ defined(_DLL) && !defined(_STATIC_CPPLIB) / !defined(_DLL) || defined(_STATIC_CPPLIB) vvv
 #define _CRTIMP2_IMPORT
-#endif
-#endif // _CRTIMP2_IMPORT
+#endif // ^^^ !defined(_DLL) || defined(_STATIC_CPPLIB) ^^^
+#endif // !defined(_CRTIMP2_IMPORT)
 
 #ifndef _CRTIMP2_PURE_IMPORT
 #ifdef _M_CEE_PURE
@@ -291,7 +291,7 @@ _EMIT_STL_WARNING(STL4001, "/clr:pure is deprecated and will be REMOVED.");
 #else
 #define _CRTIMP2_PURE_IMPORT _CRTIMP2_IMPORT
 #endif
-#endif // _CRTIMP2_PURE_IMPORT
+#endif // !defined(_CRTIMP2_PURE_IMPORT)
 
 #ifndef _CRTIMP2_PURE_IMPORT_UNLESS_CODECVT_ID_SATELLITE
 #ifdef _BUILDING_SATELLITE_CODECVT_IDS
@@ -299,7 +299,7 @@ _EMIT_STL_WARNING(STL4001, "/clr:pure is deprecated and will be REMOVED.");
 #else
 #define _CRTIMP2_PURE_IMPORT_UNLESS_CODECVT_ID_SATELLITE _CRTIMP2_PURE_IMPORT
 #endif
-#endif // _CRTIMP2_PURE_IMPORT_UNLESS_CODECVT_ID_SATELLITE
+#endif // !defined(_CRTIMP2_PURE_IMPORT_UNLESS_CODECVT_ID_SATELLITE)
 
 #ifndef _CRTDATA2_IMPORT
 #if defined(MRTDLL) && defined(_CRTBLD)
@@ -307,7 +307,7 @@ _EMIT_STL_WARNING(STL4001, "/clr:pure is deprecated and will be REMOVED.");
 #else
 #define _CRTDATA2_IMPORT _CRTIMP2_IMPORT
 #endif
-#endif // _CRTDATA2_IMPORT
+#endif // !defined(_CRTDATA2_IMPORT)
 
 #define _LOCK_LOCALE         0
 #define _LOCK_MALLOC         1
@@ -321,7 +321,7 @@ _EMIT_STL_WARNING(STL4001, "/clr:pure is deprecated and will be REMOVED.");
 #else // ^^^ modern 64-bit / less modern or 32-bit vvv
 #define _STD_ATOMIC_ALWAYS_USE_CMPXCHG16B 0
 #endif // _STL_WIN32_WINNT >= _STL_WIN32_WINNT_WINBLUE && defined(_WIN64)
-#endif // _STD_ATOMIC_ALWAYS_USE_CMPXCHG16B
+#endif // !defined(_STD_ATOMIC_ALWAYS_USE_CMPXCHG16B)
 
 #if _STD_ATOMIC_ALWAYS_USE_CMPXCHG16B == 0 && defined(_M_ARM64)
 #error ARM64 requires _STD_ATOMIC_ALWAYS_USE_CMPXCHG16B to be 1.
@@ -378,16 +378,16 @@ class _CRTIMP2_PURE_IMPORT _EmptyLockit { // empty lock class used for bin compa
 private:
     int _Locktype;
 };
-#endif // _M_CEE_PURE
+#endif // defined(_M_CEE_PURE)
 
 #ifdef _M_CEE
 #ifndef _PREPARE_CONSTRAINED_REGIONS
 #ifdef _M_CEE_PURE
 #define _PREPARE_CONSTRAINED_REGIONS 1
-#else // _M_CEE_PURE
+#else // ^^^ defined(_M_CEE_PURE) / !defined(_M_CEE_PURE) vvv
 #define _PREPARE_CONSTRAINED_REGIONS 0
-#endif // _M_CEE_PURE
-#endif // _PREPARE_CONSTRAINED_REGIONS
+#endif // ^^^ !defined(_M_CEE_PURE) ^^^
+#endif // !defined(_PREPARE_CONSTRAINED_REGIONS)
 
 #if _PREPARE_CONSTRAINED_REGIONS
 #define _BEGIN_LOCK(_Kind)                                                                  \

stl/inc/yvals_core.h

@@ -14,7 +14,7 @@
 #else
 #define _STL_COMPILER_PREPROCESSOR 1
 #endif
-#endif // _STL_COMPILER_PREPROCESSOR
+#endif // !defined(_STL_COMPILER_PREPROCESSOR)
 
 #if _STL_COMPILER_PREPROCESSOR
 
@@ -520,7 +520,7 @@
 #else // defined(_MSVC_WARNING_LEVEL) && _MSVC_WARNING_LEVEL >= 4
 #define _STL_WARNING_LEVEL 3
 #endif // defined(_MSVC_WARNING_LEVEL) && _MSVC_WARNING_LEVEL >= 4
-#endif // _STL_WARNING_LEVEL
+#endif // !defined(_STL_WARNING_LEVEL)
 
 #if _STL_WARNING_LEVEL < 3
 #error _STL_WARNING_LEVEL cannot be less than 3.
@@ -572,16 +572,16 @@
 #elif __has_cpp_attribute(nodiscard) >= 201907L
 #define _NODISCARD_CTOR           _NODISCARD
 #define _NODISCARD_CTOR_MSG(_Msg) _NODISCARD_MSG(_Msg)
-#else
+#else // ^^^ __has_cpp_attribute(nodiscard) >= 201907L / __has_cpp_attribute(nodiscard) < 201907L vvv
 #define _NODISCARD_CTOR
 #define _NODISCARD_CTOR_MSG(_Msg)
-#endif
+#endif // ^^^ defined(__has_cpp_attribute) && __has_cpp_attribute(nodiscard) < 201907L ^^^
 
 #if defined(__CUDACC__) && !defined(__clang__) // TRANSITION, VSO-568006
 #define _NODISCARD_FRIEND friend
 #else // ^^^ workaround / no workaround vvv
 #define _NODISCARD_FRIEND _NODISCARD friend
-#endif // TRANSITION, VSO-568006
+#endif // ^^^ no workaround ^^^
 
 #define _NODISCARD_REMOVE_ALG                                                                                    \
     _NODISCARD_MSG("The 'remove' and 'remove_if' algorithms return the iterator past the last element "          \
@@ -771,7 +771,7 @@
 
 #ifndef _STL_EXTRA_DISABLED_WARNINGS
 #define _STL_EXTRA_DISABLED_WARNINGS
-#endif // _STL_EXTRA_DISABLED_WARNINGS
+#endif // !defined(_STL_EXTRA_DISABLED_WARNINGS)
 
 // warning C4180: qualifier applied to function type has no meaning; ignored
 // warning C4412: function signature contains type 'meow'; C++ objects are unsafe to pass between pure code
@@ -812,7 +812,7 @@
     _STL_DISABLED_WARNING_C5053                       \
     _STL_EXTRA_DISABLED_WARNINGS
 // clang-format on
-#endif // _STL_DISABLED_WARNINGS
+#endif // !defined(_STL_DISABLED_WARNINGS)
 
 // warning: constexpr if is a C++17 extension [-Wc++17-extensions]
 // warning: explicit(bool) is a C++20 extension [-Wc++20-extensions]
@@ -836,7 +836,7 @@
 #else // ^^^ defined(__clang__) / !defined(__clang__) vvv
 #define _STL_DISABLE_CLANG_WARNINGS
 #endif // ^^^ !defined(__clang__) ^^^
-#endif // _STL_DISABLE_CLANG_WARNINGS
+#endif // !defined(_STL_DISABLE_CLANG_WARNINGS)
 
 #ifndef _STL_RESTORE_CLANG_WARNINGS
 #ifdef __clang__
@@ -844,7 +844,7 @@
 #else // ^^^ defined(__clang__) / !defined(__clang__) vvv
 #define _STL_RESTORE_CLANG_WARNINGS
 #endif // ^^^ !defined(__clang__) ^^^
-#endif // _STL_RESTORE_CLANG_WARNINGS
+#endif // !defined(_STL_RESTORE_CLANG_WARNINGS)
 
 // clang-format off
 #ifndef _STL_DISABLE_DEPRECATED_WARNING
@@ -872,7 +872,7 @@
 #else // vvv MSVC vvv
 #define _STL_RESTORE_DEPRECATED_WARNING _Pragma("warning(pop)")
 #endif // ^^^ MSVC ^^^
-#endif // _STL_RESTORE_DEPRECATED_WARNING
+#endif // !defined(_STL_RESTORE_DEPRECATED_WARNING)
 
 #define _CPPLIB_VER       650
 #define _MSVC_STL_VERSION 143
@@ -896,7 +896,7 @@ _EMIT_STL_ERROR(STL1001, "Unexpected compiler version, expected MSVC 19.38 or ne
 #else // vvv other compilers vvv
 // not attempting to detect other compilers
 #endif // ^^^ other compilers ^^^
-#endif // _ALLOW_COMPILER_AND_STL_VERSION_MISMATCH
+#endif // !defined(_ALLOW_COMPILER_AND_STL_VERSION_MISMATCH)
 
 #ifndef _HAS_STATIC_RTTI
 #define _HAS_STATIC_RTTI 1
@@ -950,12 +950,12 @@ _EMIT_STL_ERROR(STL1001, "Unexpected compiler version, expected MSVC 19.38 or ne
 // N4190 Removing auto_ptr, random_shuffle(), And Old <functional> Stuff
 #ifndef _HAS_AUTO_PTR_ETC
 #define _HAS_AUTO_PTR_ETC (!_HAS_CXX17)
-#endif // _HAS_AUTO_PTR_ETC
+#endif // !defined(_HAS_AUTO_PTR_ETC)
 
 // P0003R5 Removing Dynamic Exception Specifications
 #ifndef _HAS_UNEXPECTED
 #define _HAS_UNEXPECTED (!_HAS_CXX17)
-#endif // _HAS_UNEXPECTED
+#endif // !defined(_HAS_UNEXPECTED)
 
 #if _HAS_UNEXPECTED && _HAS_CXX23
 _EMIT_STL_ERROR(STL1004, "C++98 unexpected() is incompatible with C++23 unexpected<E>.");
@@ -964,12 +964,12 @@ _EMIT_STL_ERROR(STL1004, "C++98 unexpected() is incompatible with C++23 unexpect
 // P0004R1 Removing Deprecated Iostreams Aliases
 #ifndef _HAS_OLD_IOSTREAMS_MEMBERS
 #define _HAS_OLD_IOSTREAMS_MEMBERS (!_HAS_CXX17)
-#endif // _HAS_OLD_IOSTREAMS_MEMBERS
+#endif // !defined(_HAS_OLD_IOSTREAMS_MEMBERS)
 
 // P0298R3 std::byte
 #ifndef _HAS_STD_BYTE
 #define _HAS_STD_BYTE _HAS_CXX17 // inspected by GSL, do not remove
-#endif // _HAS_STD_BYTE
+#endif // !defined(_HAS_STD_BYTE)
 
 // P0302R1 Removing Allocator Support In std::function
 // LWG-2385 function::assign allocator argument doesn't make sense
@@ -977,12 +977,12 @@ _EMIT_STL_ERROR(STL1004, "C++98 unexpected() is incompatible with C++23 unexpect
 // LWG-2976 Dangling uses_allocator specialization for packaged_task
 #ifndef _HAS_FUNCTION_ALLOCATOR_SUPPORT
 #define _HAS_FUNCTION_ALLOCATOR_SUPPORT (!_HAS_CXX17)
-#endif // _HAS_FUNCTION_ALLOCATOR_SUPPORT
+#endif // !defined(_HAS_FUNCTION_ALLOCATOR_SUPPORT)
 
 // The non-Standard std::tr1 namespace and TR1-only machinery
 #ifndef _HAS_TR1_NAMESPACE
 #define _HAS_TR1_NAMESPACE (!_HAS_CXX17)
-#endif // _HAS_TR1_NAMESPACE
+#endif // !defined(_HAS_TR1_NAMESPACE)
 
 // STL4000 is "_STATIC_CPPLIB is deprecated", currently in yvals.h
 // STL4001 is "/clr:pure is deprecated", currently in yvals.h
@@ -1004,7 +1004,7 @@ _EMIT_STL_ERROR(STL1004, "C++98 unexpected() is incompatible with C++23 unexpect
 // Enforcement of matching allocator value_types
 #ifndef _ENFORCE_MATCHING_ALLOCATORS
 #define _ENFORCE_MATCHING_ALLOCATORS _HAS_CXX17
-#endif // _ENFORCE_MATCHING_ALLOCATORS
+#endif // !defined(_ENFORCE_MATCHING_ALLOCATORS)
 
 #define _MISMATCHED_ALLOCATOR_MESSAGE(_CONTAINER, _VALUE_TYPE)                                                      \
     _CONTAINER " requires that Allocator's value_type match " _VALUE_TYPE " (See N4950 [container.alloc.reqmts]/5)" \
@@ -1014,7 +1014,7 @@ _EMIT_STL_ERROR(STL1004, "C++98 unexpected() is incompatible with C++23 unexpect
 // Enforcement of Standard facet specializations
 #ifndef _ENFORCE_FACET_SPECIALIZATIONS
 #define _ENFORCE_FACET_SPECIALIZATIONS 0
-#endif // _ENFORCE_FACET_SPECIALIZATIONS
+#endif // !defined(_ENFORCE_FACET_SPECIALIZATIONS)
 
 #define _FACET_SPECIALIZATION_MESSAGE                                                  \
     "Unsupported facet specialization; see N4950 [locale.category]. "                  \
@@ -1025,7 +1025,7 @@ _EMIT_STL_ERROR(STL1004, "C++98 unexpected() is incompatible with C++23 unexpect
 // depicted in the Standard.
 #ifndef _STL_OPTIMIZE_SYSTEM_ERROR_OPERATORS
 #define _STL_OPTIMIZE_SYSTEM_ERROR_OPERATORS 1
-#endif // _STL_OPTIMIZE_SYSTEM_ERROR_OPERATORS
+#endif // !defined(_STL_OPTIMIZE_SYSTEM_ERROR_OPERATORS)
 
 // Controls whether the STL will force /fp:fast to enable vectorization of algorithms defined
 // in the standard as special cases; such as reduce, transform_reduce, inclusive_scan, exclusive_scan
@@ -1034,8 +1034,8 @@ _EMIT_STL_ERROR(STL1004, "C++98 unexpected() is incompatible with C++23 unexpect
 #define _STD_VECTORIZE_WITH_FLOAT_CONTROL 0
 #else // ^^^ floating-point exceptions enabled / floating-point exceptions disabled (default) vvv
 #define _STD_VECTORIZE_WITH_FLOAT_CONTROL 1
-#endif // _M_FP_EXCEPT
-#endif // _STD_VECTORIZE_WITH_FLOAT_CONTROL
+#endif // ^^^ floating-point exceptions disabled (default) ^^^
+#endif // !defined(_STD_VECTORIZE_WITH_FLOAT_CONTROL)
 
 // P0174R2 Deprecating Vestigial Library Parts
 // P0521R0 Deprecating shared_ptr::unique()
@@ -1527,47 +1527,47 @@ _EMIT_STL_ERROR(STL1004, "C++98 unexpected() is incompatible with C++23 unexpect
 // P0619R4 Removing C++17-Deprecated Features
 #ifndef _HAS_FEATURES_REMOVED_IN_CXX20
 #define _HAS_FEATURES_REMOVED_IN_CXX20 (!_HAS_CXX20)
-#endif // _HAS_FEATURES_REMOVED_IN_CXX20
+#endif // !defined(_HAS_FEATURES_REMOVED_IN_CXX20)
 
 #ifndef _HAS_DEPRECATED_ADAPTOR_TYPEDEFS
 #define _HAS_DEPRECATED_ADAPTOR_TYPEDEFS (_HAS_FEATURES_REMOVED_IN_CXX20)
-#endif // _HAS_DEPRECATED_ADAPTOR_TYPEDEFS
+#endif // !defined(_HAS_DEPRECATED_ADAPTOR_TYPEDEFS)
 
 #ifndef _HAS_DEPRECATED_ALLOCATOR_MEMBERS
 #define _HAS_DEPRECATED_ALLOCATOR_MEMBERS (_HAS_FEATURES_REMOVED_IN_CXX20)
-#endif // _HAS_DEPRECATED_ALLOCATOR_MEMBERS
+#endif // !defined(_HAS_DEPRECATED_ALLOCATOR_MEMBERS)
 
 #ifndef _HAS_DEPRECATED_ALLOCATOR_VOID
 #define _HAS_DEPRECATED_ALLOCATOR_VOID (_HAS_FEATURES_REMOVED_IN_CXX20)
-#endif // _HAS_DEPRECATED_ALLOCATOR_VOID
+#endif // !defined(_HAS_DEPRECATED_ALLOCATOR_VOID)
 
 #ifndef _HAS_DEPRECATED_IS_LITERAL_TYPE
 #define _HAS_DEPRECATED_IS_LITERAL_TYPE (_HAS_FEATURES_REMOVED_IN_CXX20)
-#endif // _HAS_DEPRECATED_IS_LITERAL_TYPE
+#endif // !defined(_HAS_DEPRECATED_IS_LITERAL_TYPE)
 
 #ifndef _HAS_DEPRECATED_NEGATORS
 #define _HAS_DEPRECATED_NEGATORS (_HAS_FEATURES_REMOVED_IN_CXX20)
-#endif // _HAS_DEPRECATED_NEGATORS
+#endif // !defined(_HAS_DEPRECATED_NEGATORS)
 
 #ifndef _HAS_DEPRECATED_RAW_STORAGE_ITERATOR
 #define _HAS_DEPRECATED_RAW_STORAGE_ITERATOR (_HAS_FEATURES_REMOVED_IN_CXX20)
-#endif // _HAS_DEPRECATED_RAW_STORAGE_ITERATOR
+#endif // !defined(_HAS_DEPRECATED_RAW_STORAGE_ITERATOR)
 
 #ifndef _HAS_DEPRECATED_RESULT_OF
 #define _HAS_DEPRECATED_RESULT_OF (_HAS_FEATURES_REMOVED_IN_CXX20)
-#endif // _HAS_DEPRECATED_RESULT_OF
+#endif // !defined(_HAS_DEPRECATED_RESULT_OF)
 
 #ifndef _HAS_DEPRECATED_SHARED_PTR_UNIQUE
 #define _HAS_DEPRECATED_SHARED_PTR_UNIQUE (_HAS_FEATURES_REMOVED_IN_CXX20)
-#endif // _HAS_DEPRECATED_SHARED_PTR_UNIQUE
+#endif // !defined(_HAS_DEPRECATED_SHARED_PTR_UNIQUE)
 
 #ifndef _HAS_DEPRECATED_TEMPORARY_BUFFER
 #define _HAS_DEPRECATED_TEMPORARY_BUFFER (_HAS_FEATURES_REMOVED_IN_CXX20)
-#endif // _HAS_DEPRECATED_TEMPORARY_BUFFER
+#endif // !defined(_HAS_DEPRECATED_TEMPORARY_BUFFER)
 
 #ifndef _HAS_DEPRECATED_UNCAUGHT_EXCEPTION
 #define _HAS_DEPRECATED_UNCAUGHT_EXCEPTION (_HAS_FEATURES_REMOVED_IN_CXX20)
-#endif // _HAS_DEPRECATED_UNCAUGHT_EXCEPTION
+#endif // !defined(_HAS_DEPRECATED_UNCAUGHT_EXCEPTION)
 
 #if _HAS_DEPRECATED_ADAPTOR_TYPEDEFS
 #define _ARGUMENT_TYPE_NAME        argument_type
@@ -1579,22 +1579,22 @@ _EMIT_STL_ERROR(STL1004, "C++98 unexpected() is incompatible with C++23 unexpect
 #define _FIRST_ARGUMENT_TYPE_NAME  _Unnameable_first_argument
 #define _SECOND_ARGUMENT_TYPE_NAME _Unnameable_second_argument
 #define _RESULT_TYPE_NAME          _Unnameable_result
-#endif // !_HAS_DEPRECATED_ADAPTOR_TYPEDEFS
+#endif // ^^^ !_HAS_DEPRECATED_ADAPTOR_TYPEDEFS ^^^
 
 // P1423R3 char8_t Backward Compatibility Remediation
 // Controls whether we allow the stream insertions this proposal forbids
 #ifndef _HAS_STREAM_INSERTION_OPERATORS_DELETED_IN_CXX20
 #define _HAS_STREAM_INSERTION_OPERATORS_DELETED_IN_CXX20 (_HAS_FEATURES_REMOVED_IN_CXX20)
-#endif // _HAS_STREAM_INSERTION_OPERATORS_DELETED_IN_CXX20
+#endif // !defined(_HAS_STREAM_INSERTION_OPERATORS_DELETED_IN_CXX20)
 
 #ifndef _HAS_FEATURES_REMOVED_IN_CXX23
 #define _HAS_FEATURES_REMOVED_IN_CXX23 (!_HAS_CXX23)
-#endif // _HAS_FEATURES_REMOVED_IN_CXX23
+#endif // !defined(_HAS_FEATURES_REMOVED_IN_CXX23)
 
 // P2186R2 Removing Garbage Collection Support
 #ifndef _HAS_GARBAGE_COLLECTION_SUPPORT_DELETED_IN_CXX23
 #define _HAS_GARBAGE_COLLECTION_SUPPORT_DELETED_IN_CXX23 (_HAS_FEATURES_REMOVED_IN_CXX23)
-#endif // _HAS_GARBAGE_COLLECTION_SUPPORT_DELETED_IN_CXX23
+#endif // !defined(_HAS_GARBAGE_COLLECTION_SUPPORT_DELETED_IN_CXX23)
 
 // C++14
 #define __cpp_lib_chrono_udls                      201304L
@@ -1626,7 +1626,7 @@ _EMIT_STL_ERROR(STL1004, "C++98 unexpected() is incompatible with C++23 unexpect
 #define __cpp_lib_robust_nonmodifying_seq_ops      201304L
 #ifndef _M_CEE_PURE
 #define __cpp_lib_shared_timed_mutex 201402L
-#endif // _M_CEE_PURE
+#endif // !defined(_M_CEE_PURE)
 #define __cpp_lib_string_udls                  201304L
 #define __cpp_lib_transformation_trait_aliases 201304L
 #define __cpp_lib_tuple_element_t              201402L
@@ -1678,7 +1678,7 @@ _EMIT_STL_ERROR(STL1004, "C++98 unexpected() is incompatible with C++23 unexpect
 #define __cpp_lib_not_fn                            201603L
 #ifndef _M_CEE_PURE
 #define __cpp_lib_parallel_algorithm 201603L
-#endif // _M_CEE_PURE
+#endif // !defined(_M_CEE_PURE)
 #define __cpp_lib_raw_memory_algorithms 201606L
 #define __cpp_lib_sample                201603L
 #define __cpp_lib_scoped_lock           201703L
@@ -1692,11 +1692,11 @@ _EMIT_STL_ERROR(STL1004, "C++98 unexpected() is incompatible with C++23 unexpect
 
 #ifdef __cpp_char8_t
 #define __cpp_lib_char8_t 201907L
-#endif // __cpp_char8_t
+#endif // defined(__cpp_char8_t)
 
 #ifdef __cpp_impl_coroutine
 #define __cpp_lib_coroutine 201902L
-#endif // __cpp_impl_coroutine
+#endif // defined(__cpp_impl_coroutine)
 
 #if _HAS_CXX20
 #if !defined(__EDG__) || defined(__INTELLISENSE__) // TRANSITION, GH-395
@@ -1757,13 +1757,13 @@ _EMIT_STL_ERROR(STL1004, "C++98 unexpected() is incompatible with C++23 unexpect
 
 #ifndef __clang__ // TRANSITION, LLVM-48860
 #define __cpp_lib_is_layout_compatible 201907L
-#endif // __clang__
+#endif // !defined(__clang__)
 
 #define __cpp_lib_is_nothrow_convertible 201806L
 
 #ifndef __clang__ // TRANSITION, LLVM-48860
 #define __cpp_lib_is_pointer_interconvertible 201907L
-#endif // __clang__
+#endif // !defined(__clang__)
 
 #define __cpp_lib_jthread                 201911L
 #define __cpp_lib_latch                   201907L
@@ -1889,7 +1889,7 @@ _EMIT_STL_ERROR(STL1004, "C++98 unexpected() is incompatible with C++23 unexpect
 #elif _HAS_CXX17
 #define __cpp_lib_execution 201603L // P0024R2 Parallel Algorithms
 #endif // language mode
-#endif // _M_CEE_PURE
+#endif // !defined(_M_CEE_PURE)
 
 #if _HAS_CXX23 && defined(__cpp_lib_concepts) // TRANSITION, GH-395
 #define __cpp_lib_optional 202110L // P0798R8 Monadic Operations For optional
@@ -1932,8 +1932,8 @@ _EMIT_STL_ERROR(STL1004, "C++98 unexpected() is incompatible with C++23 unexpect
 #ifndef _ALLOW_RTCc_IN_STL
 #error /RTCc rejects conformant code, so it is not supported by the C++ Standard Library. Either remove this \
 compiler option, or define _ALLOW_RTCc_IN_STL to suppress this error.
-#endif // _ALLOW_RTCc_IN_STL
-#endif // _RTC_CONVERSION_CHECKS_ENABLED
+#endif // !defined(_ALLOW_RTCc_IN_STL)
+#endif // defined(_RTC_CONVERSION_CHECKS_ENABLED)
 
 #define _STRINGIZEX(x)  #x
 #define _STRINGIZE(x)   _STRINGIZEX(x)
@@ -1989,27 +1989,27 @@ compiler option, or define _ALLOW_RTCc_IN_STL to suppress this error.
 // The earliest Windows supported by this implementation is Windows 7
 #define _STL_WIN32_WINNT _STL_WIN32_WINNT_WIN7
 #endif // ^^^ !defined(_M_ARM) && !defined(_M_ARM64) && !defined(_ONECORE) && !defined(_CRT_APP) ^^^
-#endif // _STL_WIN32_WINNT
+#endif // !defined(_STL_WIN32_WINNT)
 
 #ifdef __cpp_noexcept_function_type
 #define _NOEXCEPT_FNPTR noexcept
-#else
+#else // ^^^ defined(__cpp_noexcept_function_type) / !defined(__cpp_noexcept_function_type) vvv
 #define _NOEXCEPT_FNPTR
-#endif // __cpp_noexcept_function_type
+#endif // ^^^ !defined(__cpp_noexcept_function_type) ^^^
 
 #ifdef __clang__
 #define _STL_INTRIN_HEADER <intrin.h>
 #define _STL_UNREACHABLE   __builtin_unreachable()
-#else // ^^^ clang / other vvv
+#else // ^^^ defined(__clang__) / !defined(__clang__) vvv
 #define _STL_INTRIN_HEADER <intrin0.h>
 #define _STL_UNREACHABLE   __assume(false)
-#endif // __clang__
+#endif // ^^^ !defined(__clang__) ^^^
 
 #ifdef _ENABLE_STL_INTERNAL_CHECK
 #define _STL_INTERNAL_STATIC_ASSERT(...) static_assert(__VA_ARGS__, #__VA_ARGS__)
-#else // ^^^ _ENABLE_STL_INTERNAL_CHECK / !_ENABLE_STL_INTERNAL_CHECK vvv
+#else // ^^^ defined(_ENABLE_STL_INTERNAL_CHECK) / !defined(_ENABLE_STL_INTERNAL_CHECK) vvv
 #define _STL_INTERNAL_STATIC_ASSERT(...)
-#endif // _ENABLE_STL_INTERNAL_CHECK
+#endif // ^^^ !defined(_ENABLE_STL_INTERNAL_CHECK) ^^^
 
 #endif // _STL_COMPILER_PREPROCESSOR
 #endif // _YVALS_CORE_H_

stl/src/atomic_wait.cpp

@@ -94,7 +94,7 @@ namespace {
 #else // ^^^ _STL_WIN32_WINNT >= _STL_WIN32_WINNT_WIN8 / _STL_WIN32_WINNT < _STL_WIN32_WINNT_WIN8 vvv
 #define _ATOMIC_WAIT_ON_ADDRESS_STATICALLY_AVAILABLE 0
 #endif // ^^^ _STL_WIN32_WINNT < _STL_WIN32_WINNT_WIN8 ^^^
-#endif // _ATOMIC_WAIT_ON_ADDRESS_STATICALLY_AVAILABLE
+#endif // !defined(_ATOMIC_WAIT_ON_ADDRESS_STATICALLY_AVAILABLE)
 
 #if _ATOMIC_WAIT_ON_ADDRESS_STATICALLY_AVAILABLE
 

stl/src/dllmain.cpp

@@ -8,7 +8,7 @@
 #ifdef _CRT_APP
 // free static resource used by causality
 extern "C" void __cdecl __crtCleanupCausalityStaticFactories();
-#endif // _CRT_APP
+#endif // defined(_CRT_APP)
 
 extern "C" BOOL APIENTRY DllMain(HMODULE /* hModule */, DWORD ul_reason_for_call, [[maybe_unused]] LPVOID lpReserved) {
     if (ul_reason_for_call == DLL_PROCESS_DETACH) {
@@ -16,7 +16,7 @@ extern "C" BOOL APIENTRY DllMain(HMODULE /* hModule */, DWORD ul_reason_for_call
         if (lpReserved == nullptr) { // only when the process is not terminating
             __crtCleanupCausalityStaticFactories();
         }
-#endif // _CRT_APP
+#endif // defined(_CRT_APP)
     }
     return TRUE;
 }

stl/src/excptptr.cpp

@@ -8,7 +8,7 @@
 
 #ifndef _VCRT_ALLOW_INTERNALS
 #define _VCRT_ALLOW_INTERNALS
-#endif // _VCRT_ALLOW_INTERNALS
+#endif // !defined(_VCRT_ALLOW_INTERNALS)
 
 #include <Unknwn.h>
 #include <cstdlib> // for abort
@@ -171,7 +171,7 @@ namespace {
         const auto _CopyFunc = reinterpret_cast<void*>(_ThrowImageBase + _PType->copyFunction);
 #else // ^^^ _EH_RELATIVE_TYPEINFO / !_EH_RELATIVE_TYPEINFO vvv
         const auto _CopyFunc = _PType->copyFunction;
-#endif // _EH_RELATIVE_TYPEINFO
+#endif // ^^^ !_EH_RELATIVE_TYPEINFO ^^^
 
         const auto _Adjusted = __AdjustPointer(const_cast<void*>(_Src), _PType->thisDisplacement);
         if (_PType->properties & CT_HasVirtualBase) {
@@ -270,7 +270,7 @@ namespace {
                 static_cast<uintptr_t>(_CatchableTypeArray->arrayOfCatchableTypes[0]) + _ThrowImageBase);
 #else // ^^^ _EH_RELATIVE_TYPEINFO / !_EH_RELATIVE_TYPEINFO vvv
             const auto _PType = _PThrow->pCatchableTypeArray->arrayOfCatchableTypes[0];
-#endif // _EH_RELATIVE_TYPEINFO
+#endif // ^^^ !_EH_RELATIVE_TYPEINFO ^^^
 
             if (_PThrow->pmfnUnwind) {
                 // The exception was a user defined type with a nontrivial destructor, call it
@@ -281,7 +281,7 @@ namespace {
                     reinterpret_cast<void*>(_PThrow->pmfnUnwind + _ThrowImageBase));
 #else // ^^^ _EH_RELATIVE_TYPEINFO && !defined(_M_CEE_PURE) / !_EH_RELATIVE_TYPEINFO && !defined(_M_CEE_PURE) vvv
                 _CallMemberFunction0(_CppEhRecord.params.pExceptionObject, _PThrow->pmfnUnwind);
-#endif
+#endif // ^^^ !_EH_RELATIVE_TYPEINFO && !defined(_M_CEE_PURE) ^^^
             } else if (_PType->properties & CT_IsWinRTHandle) {
                 const auto _PUnknown = *static_cast<IUnknown* const*>(_CppEhRecord.params.pExceptionObject);
                 if (_PUnknown) {
@@ -337,7 +337,7 @@ namespace {
             static_cast<uintptr_t>(_CatchableTypeArray->arrayOfCatchableTypes[0]) + _ThrowImageBase);
 #else // ^^^ _EH_RELATIVE_TYPEINFO / !_EH_RELATIVE_TYPEINFO vvv
         const auto _PType = _PThrow->pCatchableTypeArray->arrayOfCatchableTypes[0];
-#endif // _EH_RELATIVE_TYPEINFO
+#endif // ^^^ !_EH_RELATIVE_TYPEINFO ^^^
 
         const auto _ExceptionObjectSize = static_cast<size_t>(_PType->sizeOrOffset);
         const auto _AllocSize           = sizeof(_ExceptionPtr_normal) + _ExceptionObjectSize;
@@ -386,7 +386,7 @@ namespace {
                 static_cast<uintptr_t>(_InnerCatchableTypeArray->arrayOfCatchableTypes[0]) + _InnerThrowImageBase);
 #else // ^^^ _EH_RELATIVE_TYPEINFO / !_EH_RELATIVE_TYPEINFO vvv
             const auto _PInnerType = _PInnerThrow->pCatchableTypeArray->arrayOfCatchableTypes[0];
-#endif // _EH_RELATIVE_TYPEINFO
+#endif // ^^^ !_EH_RELATIVE_TYPEINFO ^^^
 
             const auto _InnerExceptionSize = static_cast<size_t>(_PInnerType->sizeOrOffset);
             const auto _InnerAllocSize     = sizeof(_ExceptionPtr_normal) + _InnerExceptionSize;
@@ -496,9 +496,9 @@ _CRTIMP2_PURE void __CLRCALL_PURE_OR_CDECL __ExceptionPtrCurrentException(void*
         const auto _ThrowImageBase = reinterpret_cast<uintptr_t>(_CppRecord.params.pThrowImageBase);
         const auto _CatchableTypeArray =
             reinterpret_cast<const CatchableTypeArray*>(_ThrowImageBase + _PThrow->pCatchableTypeArray);
-#else
+#else // ^^^ _EH_RELATIVE_TYPEINFO / !_EH_RELATIVE_TYPEINFO vvv
         const auto _CatchableTypeArray = _PThrow->pCatchableTypeArray;
-#endif // _EH_RELATIVE_TYPEINFO
+#endif // ^^^ !_EH_RELATIVE_TYPEINFO ^^^
 
         if (_CatchableTypeArray->nCatchableTypes <= 0) {
             // Ditto corrupted.
@@ -511,7 +511,7 @@ _CRTIMP2_PURE void __CLRCALL_PURE_OR_CDECL __ExceptionPtrCurrentException(void*
             static_cast<uintptr_t>(_CatchableTypeArray->arrayOfCatchableTypes[0]) + _ThrowImageBase);
 #else // ^^^ _EH_RELATIVE_TYPEINFO / !_EH_RELATIVE_TYPEINFO vvv
         const auto _PType              = _PThrow->pCatchableTypeArray->arrayOfCatchableTypes[0];
-#endif // _EH_RELATIVE_TYPEINFO
+#endif // ^^^ !_EH_RELATIVE_TYPEINFO ^^^
 
         // Alloc memory on stack for exception object. This might cause a stack overflow SEH exception, or another C++
         // exception when copying the C++ exception object. In that case, we just let that become the thrown exception.

stl/src/ppltasks.cpp

@@ -204,7 +204,7 @@ namespace Concurrency {
             }
         }
 
-#else
+#else // ^^^ defined(_CRT_APP) / !defined(_CRT_APP) vvv
         _CRTIMP2 void __thiscall _TaskEventLogger::_LogScheduleTask(bool) {}
 
         _CRTIMP2 void __thiscall _TaskEventLogger::_LogTaskCompleted() {}
@@ -216,7 +216,7 @@ namespace Concurrency {
         _CRTIMP2 void __thiscall _TaskEventLogger::_LogWorkItemStarted() {}
 
         _CRTIMP2 void __thiscall _TaskEventLogger::_LogWorkItemCompleted() {}
-#endif
+#endif // ^^^ !defined(_CRT_APP) ^^^
 
 #if defined(_CRT_APP) || defined(UNDOCKED_WINDOWS_UCRT)
         using namespace ABI::Windows::Foundation;
@@ -317,7 +317,8 @@ namespace Concurrency {
             return false;
         }
 
-#else
+#else // ^^^ defined(_CRT_APP) || defined(UNDOCKED_WINDOWS_UCRT)
+      //                                         / !defined(_CRT_APP) && !defined(UNDOCKED_WINDOWS_UCRT) vvv
         _CRTIMP2 void __thiscall _ContextCallback::_CallInContext(_CallbackFunction _Func, bool) const {
             _Func();
         }
@@ -335,16 +336,16 @@ namespace Concurrency {
         _CRTIMP2 bool __cdecl _Task_impl_base::_IsNonBlockingThread() {
             return false;
         }
-#endif
+#endif // ^^^ !defined(_CRT_APP) && !defined(UNDOCKED_WINDOWS_UCRT) ^^^
     } // namespace details
 
 #ifdef _CRT_APP
     _CRTIMP2 __thiscall task_continuation_context::task_continuation_context()
         : _ContextCallback(true), _M_RunInline(false) {}
-#else
+#else // ^^^ defined(_CRT_APP) / !defined(_CRT_APP) vvv
     _CRTIMP2 __thiscall task_continuation_context::task_continuation_context()
         : _ContextCallback(false), _M_RunInline(false) {}
-#endif
+#endif // ^^^ !defined(_CRT_APP) ^^^
 
 } // namespace Concurrency
 

stl/src/taskscheduler.cpp

@@ -55,7 +55,7 @@ namespace Concurrency {
             _STL_host_status _Get_STL_host_status() {
 #ifdef CRTDLL2
                 return _STL_host_status::_Dll;
-#else // ^^^ CRTDLL2 / !CRTDLL2 vvv
+#else // ^^^ defined(CRTDLL2) / !defined(CRTDLL2) vvv
                 HANDLE _HExe = _Call_get_module_handle_ex(GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT, nullptr);
                 if (_HExe == nullptr) {
                     return _STL_host_status::_Unknown;
@@ -64,7 +64,7 @@ namespace Concurrency {
                 } else {
                     return _STL_host_status::_Dll;
                 }
-#endif // CRTDLL2
+#endif // ^^^ !defined(CRTDLL2) ^^^
             }
 
 #ifdef CRTDLL2
@@ -73,7 +73,7 @@ namespace Concurrency {
             // code is sufficient.
             void _Increment_outstanding() {}
             void _Decrement_outstanding() {}
-#else // ^^^ CRTDLL2 / !CRTDLL2 vvv
+#else // ^^^ defined(CRTDLL2) / !defined(CRTDLL2) vvv
             size_t _Outstanding_tasks = 0;
             _STD mutex _Task_cv_mutex;
             _STD condition_variable _Task_cv;
@@ -114,7 +114,7 @@ namespace Concurrency {
                 }
             };
             _Task_scheduler_main_block _Task_scheduler_main_block_instance;
-#endif // CRTDLL2
+#endif // ^^^ !defined(CRTDLL2) ^^^
 
             void CALLBACK _Task_scheduler_callback(PTP_CALLBACK_INSTANCE _Pci, PVOID _Args, PTP_WORK) noexcept {
                 _Increment_outstanding();

stl/src/ushiostr.cpp

@@ -27,7 +27,7 @@ __PURE_APPDOMAIN_GLOBAL extern wostream* _Ptr_wcout = nullptr;
 __PURE_APPDOMAIN_GLOBAL extern wostream* _Ptr_wcerr = nullptr;
 __PURE_APPDOMAIN_GLOBAL extern wostream* _Ptr_wclog = nullptr;
 _STD_END
-#else
+#else // ^^^ defined(_M_CEE_PURE) / !defined(_M_CEE_PURE) vvv
 _STD_BEGIN
 __PURE_APPDOMAIN_GLOBAL extern _CRTDATA2_IMPORT wistream* _Ptr_wcin  = nullptr;
 __PURE_APPDOMAIN_GLOBAL extern _CRTDATA2_IMPORT wostream* _Ptr_wcout = nullptr;
@@ -35,4 +35,4 @@ __PURE_APPDOMAIN_GLOBAL extern _CRTDATA2_IMPORT wostream* _Ptr_wcerr = nullptr;
 __PURE_APPDOMAIN_GLOBAL extern _CRTDATA2_IMPORT wostream* _Ptr_wclog = nullptr;
 _STD_END
 #include "wiostrea.cpp"
-#endif
+#endif // ^^^ !defined(_M_CEE_PURE) ^^^

stl/src/vector_algorithms.cpp

@@ -15,7 +15,7 @@ extern "C" long __isa_enabled;
 
 #ifndef _DEBUG
 #pragma optimize("t", on) // Override /Os with /Ot for this TU
-#endif // !_DEBUG
+#endif // !defined(_DEBUG)
 
 namespace {
     bool _Use_avx2() noexcept {

stl/src/winapisupp.cpp

@@ -138,7 +138,7 @@ extern "C" int __crt_IsPackagedAppHelper() {
 extern "C" _CRTIMP2 BOOL __cdecl __crtIsPackagedApp() {
 #ifdef _CRT_APP
     return TRUE;
-#else
+#else // ^^^ defined(_CRT_APP) / !defined(_CRT_APP) vvv
     static int isPackaged = -1; // Initialize to undefined state
 
     // If we've already made this check, just return the prev result
@@ -147,7 +147,7 @@ extern "C" _CRTIMP2 BOOL __cdecl __crtIsPackagedApp() {
     }
 
     return (isPackaged > 0) ? TRUE : FALSE;
-#endif
+#endif // ^^^ !defined(_CRT_APP) ^^^
 }
 
 #endif // !defined(_CRT_WINDOWS) && !defined(UNDOCKED_WINDOWS_UCRT)

stl/src/xmbtowc.cpp

@@ -158,6 +158,6 @@ _MRTIMP2 _Success_(return >= 0) int __cdecl _Mbrtowc(
 _MRTIMP2 int __cdecl _Mbrtowc(unsigned short* pwc, const char* s, size_t n, mbstate_t* pst, const _Cvtvec* ploc) {
     return _Mbrtowc(reinterpret_cast<wchar_t*>(pwc), s, n, pst, ploc);
 }
-#endif // MRTDLL
+#endif // defined(MRTDLL)
 
 _END_EXTERN_C_UNLESS_PURE

stl/src/xwcscoll.cpp

@@ -71,6 +71,6 @@ _CRTIMP2_PURE int __CLRCALL_PURE_OR_CDECL _Wcscoll(const unsigned short* string1
     return _Wcscoll(reinterpret_cast<const wchar_t*>(string1), reinterpret_cast<const wchar_t*>(end1),
         reinterpret_cast<const wchar_t*>(string2), reinterpret_cast<const wchar_t*>(end2), ploc);
 }
-#endif // MRTDLL
+#endif // defined(MRTDLL)
 
 _END_EXTERN_C_UNLESS_PURE

stl/src/xwcsxfrm.cpp

@@ -104,6 +104,6 @@ _CRTIMP2_PURE size_t __CLRCALL_PURE_OR_CDECL _Wcsxfrm(unsigned short* string1, u
     return _Wcsxfrm(reinterpret_cast<wchar_t*>(string1), reinterpret_cast<wchar_t*>(end1),
         reinterpret_cast<const wchar_t*>(string2), reinterpret_cast<const wchar_t*>(end2), ploc);
 }
-#endif // MRTDLL
+#endif // defined(MRTDLL)
 
 _END_EXTERN_C_UNLESS_PURE

stl/src/xwctomb.cpp

@@ -89,7 +89,7 @@ _CRTIMP2_PURE _Success_(return != -1) int __CLRCALL_PURE_OR_CDECL
 _CRTIMP2_PURE int __CLRCALL_PURE_OR_CDECL _Wcrtomb(char* s, unsigned short wchar, mbstate_t* pst, const _Cvtvec* ploc) {
     return _Wcrtomb(s, static_cast<wchar_t>(wchar), pst, ploc);
 }
-#endif // MRTDLL
+#endif // defined(MRTDLL)
 
 // TRANSITION, ABI: __Wcrtomb_lk() is preserved for binary compatibility
 _CRTIMP2_PURE int __CLRCALL_PURE_OR_CDECL __Wcrtomb_lk(char* s, wchar_t wchar, mbstate_t* pst, const _Cvtvec* ploc) {

stl/src/xxstod.hpp

@@ -13,9 +13,9 @@
 #define NLONG 1 // 7 * NLONG == max hexadecimal digits
 #elif FBITS == 53
 #define NLONG 3
-#else // FBITS
+#else // ^^^ FBITS == 53 / FBITS != 24 && FBITS != 53 vvv
 #error Unexpected value for FBITS
-#endif // FBITS
+#endif // ^^^ FBITS != 24 && FBITS != 53 ^^^
 
 // FTYPE _Stodx(const CTYPE *s, CTYPE **endptr, long pten, int *perr)
 { // convert string to FTYPE, with checking

stl/src/xxxdtent.hpp

@@ -37,9 +37,9 @@ static const FTYPE tenth[] = {
     static_cast<FTYPE>(FLIT(2457.0) / FRAC_BITS_2 / FRAC_BITS_2),
 };
 
-#else // FBITS
+#else // ^^^ FBITS == 24 / FBITS != 24 && FBITS != 53 vvv
 #error Unexpected value for FBITS
-#endif // FBITS
+#endif // ^^^ FBITS != 24 && FBITS != 53 ^^^
 
 FTYPE FNAME(Dtento)(FTYPE* xpx, long n, int* perr) { // compute *px * 10**n
     FTYPE xpf[ACSIZE];

stl/src/xxxprec.hpp

@@ -288,9 +288,9 @@ FTYPE* FNAME(Xp_setn)(FTYPE* p, int n, long x) noexcept { // load a long integer
     FNAME(Xp_setw)(p, n, static_cast<FTYPE>(x / 10000));
     FNAME(Xp_mulh)(p, n, static_cast<FTYPE>(10000));
     FNAME(Xp_addh)(p, n, static_cast<FTYPE>(x % 10000));
-#else // FBITS
+#else // ^^^ FBITS == 24 / FBITS != 24 && FBITS != 53 vvv
 #error Unexpected value for FBITS
-#endif // FBITS
+#endif // ^^^ FBITS != 24 && FBITS != 53 ^^^
 
     return p;
 }