diff --git a/include/fast_io_core_impl/allocation/adapters.h b/include/fast_io_core_impl/allocation/adapters.h
index 8a80c26f6..e43ebb92f 100644
--- a/include/fast_io_core_impl/allocation/adapters.h
+++ b/include/fast_io_core_impl/allocation/adapters.h
@@ -1253,7 +1253,7 @@ class typed_generic_allocator_adapter
 		}
 		else
 		{
-			auto newres{alloc::allocate_zero_aligned_at_least(alignof(T), n * sizeof(T))};
+			auto newres{alloc::allocate_aligned_zero_at_least(alignof(T), n * sizeof(T))};
 			return {reinterpret_cast<T *>(newres.ptr), newres.count / sizeof(T)};
 		}
 	}
diff --git a/include/fast_io_core_impl/char_category/char_category.h b/include/fast_io_core_impl/char_category/char_category.h
index 205ec1e9c..f525a4470 100644
--- a/include/fast_io_core_impl/char_category/char_category.h
+++ b/include/fast_io_core_impl/char_category/char_category.h
@@ -1859,7 +1859,9 @@ inline constexpr bool is_c_halfwidth(char_type ch) noexcept
 	using unsigned_char_type = ::std::make_unsigned_t<char_type>;
 	if constexpr (sizeof(char_type) < sizeof(char32_t))
 	{
-		return ch;
+		constexpr unsigned_char_type halfwidth_exclaimation_mark_val{u8'!'};
+		constexpr unsigned_char_type num{94};
+		return static_cast<unsigned_char_type>(ch - halfwidth_exclaimation_mark_val) < num;
 	}
 	else if constexpr (!::std::same_as<char_type, char32_t> && sizeof(char_type) == sizeof(char32_t))
 	{
@@ -1891,7 +1893,9 @@ inline constexpr bool is_c_fullwidth(char_type ch) noexcept
 	using unsigned_char_type = ::std::make_unsigned_t<char_type>;
 	if constexpr (sizeof(char_type) < sizeof(char32_t))
 	{
-		return ch;
+		constexpr unsigned_char_type fullwidth_exclaimation_mark_val{0xFF01};
+		constexpr unsigned_char_type num{94};
+		return static_cast<unsigned_char_type>(ch - fullwidth_exclaimation_mark_val) < num;
 	}
 	else if constexpr (!::std::same_as<char_type, char32_t> && sizeof(char_type) == sizeof(char32_t))
 	{
diff --git a/include/fast_io_core_impl/freestanding/algorithm.h b/include/fast_io_core_impl/freestanding/algorithm.h
index f0ed0b983..98dcd4642 100644
--- a/include/fast_io_core_impl/freestanding/algorithm.h
+++ b/include/fast_io_core_impl/freestanding/algorithm.h
@@ -532,13 +532,13 @@ inline constexpr ForwardIt lower_bound(ForwardIt first, ForwardIt last, T const
 {
 	ForwardIt it;
 	typename ::std::iterator_traits<ForwardIt>::difference_type count, step;
-	count = last - first;
+	count = ::std::distance(first, last);
 
 	while (count > 0)
 	{
 		it = first;
 		step = count / 2;
-		it += step;
+		::std::advance(it, step);
 
 		if (comp(*it, value))
 		{
@@ -735,7 +735,7 @@ template <::std::input_iterator ForwardIt>
 inline constexpr void uninitialized_default_construct_n(ForwardIt first, ::std::size_t n) noexcept(
 	::std::is_nothrow_default_constructible_v<typename ::std::iterator_traits<ForwardIt>::value_type>)
 {
-	::fast_io::freestanding::uninitialized_default_construct(first, first + n);
+	::fast_io::freestanding::uninitialized_default_construct(first, ::std::next(first, n));
 }
 
 template <::std::input_iterator ForwardIt, typename T>
@@ -771,7 +771,7 @@ template <::std::input_iterator ForwardIt, typename T>
 inline constexpr void uninitialized_fill_n(ForwardIt first, ::std::size_t n, T const &x) noexcept(
 	::std::is_nothrow_copy_constructible_v<typename ::std::iterator_traits<ForwardIt>::value_type>)
 {
-	::fast_io::freestanding::uninitialized_fill(first, first + n, x);
+	::fast_io::freestanding::uninitialized_fill(first, ::std::next(first, n), x);
 }
 
 template <::std::forward_iterator ForwardIt>
diff --git a/include/fast_io_core_impl/freestanding/bytes.h b/include/fast_io_core_impl/freestanding/bytes.h
index 0596e8fac..afa0cebcd 100644
--- a/include/fast_io_core_impl/freestanding/bytes.h
+++ b/include/fast_io_core_impl/freestanding/bytes.h
@@ -137,6 +137,7 @@ inline constexpr ::std::byte *nonoverlapped_bytes_copy(::std::byte const *first,
 }
 
 template <typename T>
+	requires(::std::is_trivially_copyable_v<T>) // make sure the type is trivially copyable for safely using memcpy
 inline constexpr ::std::byte const *type_punning_from_bytes(::std::byte const *__restrict first,
 															T &__restrict t) noexcept
 {
@@ -164,7 +165,7 @@ inline constexpr ::std::byte const *type_punning_from_bytes(::std::byte const *_
 }
 
 template <::std::size_t n, typename T>
-	requires(n <= sizeof(T))
+	requires(n <= sizeof(T) && ::std::is_trivially_copyable_v<T>)
 inline constexpr ::std::byte *type_punning_to_bytes_n(T const &__restrict first, ::std::byte *__restrict dest) noexcept
 {
 	if constexpr (n != 0)
diff --git a/include/fast_io_core_impl/integers/crypto_hash.h b/include/fast_io_core_impl/integers/crypto_hash.h
index 5f2a74c14..71c1c0e63 100644
--- a/include/fast_io_core_impl/integers/crypto_hash.h
+++ b/include/fast_io_core_impl/integers/crypto_hash.h
@@ -281,7 +281,7 @@ inline constexpr hash_compress_t<digest_format::upper, ctx> hash_compress_upper(
 	else
 	{
 		return {reinterpret_cast<::std::byte const *>(::std::ranges::data(t)),
-				static_cast<::std::size_t>(::std::ranges::size(t)) * sizeof(T)};
+				static_cast<::std::size_t>(::std::ranges::size(t)) * sizeof(::std::ranges::range_value_t<T>)};
 	}
 }
 
@@ -296,7 +296,7 @@ inline constexpr hash_compress_t<digest_format::raw_bytes, ctx> hash_compress_ra
 	else
 	{
 		return {reinterpret_cast<::std::byte const *>(::std::ranges::data(t)),
-				static_cast<::std::size_t>(::std::ranges::size(t)) * sizeof(T)};
+				static_cast<::std::size_t>(::std::ranges::size(t)) * sizeof(::std::ranges::range_value_t<T>)};
 	}
 }
 
@@ -478,7 +478,7 @@ inline constexpr char_type *prv_srv_hash_compress_df_impl(char_type *iter, ::std
 				::std::byte buffer[digest_size];
 				auto ret{cal_hash_internal_impl<T>(base, len, buffer)};
 				return ::fast_io::details::copy_to_hash_df_commom_impl < d ==
-					   ::fast_io::manipulators::digest_format::upper > (buffer, iter, static_cast<::std::size_t>(ret - buffer));
+					   ::fast_io::manipulators::digest_format::upper > (iter, buffer, static_cast<::std::size_t>(ret - buffer));
 			}
 			else
 			{
@@ -512,7 +512,7 @@ inline constexpr char_type *prv_srv_hash_compress_df_impl(char_type *iter, ::std
 				::std::byte buffer[digest_size];
 				cal_hash_internal<T>(base, len, buffer);
 				return ::fast_io::details::copy_to_hash_df_commom_impl < d ==
-					   ::fast_io::manipulators::digest_format::upper > (buffer, iter, digest_size);
+					   ::fast_io::manipulators::digest_format::upper > (iter, buffer, digest_size);
 			}
 			else
 			{
diff --git a/include/fast_io_core_impl/operations/printimpl/print_freestanding_cxx20.h b/include/fast_io_core_impl/operations/printimpl/print_freestanding_cxx20.h
index 20df211ad..27eb12af9 100644
--- a/include/fast_io_core_impl/operations/printimpl/print_freestanding_cxx20.h
+++ b/include/fast_io_core_impl/operations/printimpl/print_freestanding_cxx20.h
@@ -141,7 +141,7 @@ inline constexpr scatter_rsv_result find_continuous_scatters_reserve_n()
 	{
 		if constexpr (sizeof...(Args) == 0)
 		{
-			return {1, 0, ::fast_io::details::intrinsics::add_or_overflow_die_chain(static_cast<::std::size_t>(0), static_cast<::std::size_t>(1))};
+			return {1, 0, 1};
 		}
 		else
 		{
diff --git a/include/fast_io_core_impl/operations/printimpl/print_freestanding_cxx26.h b/include/fast_io_core_impl/operations/printimpl/print_freestanding_cxx26.h
index 92633ef6e..e41db93f4 100644
--- a/include/fast_io_core_impl/operations/printimpl/print_freestanding_cxx26.h
+++ b/include/fast_io_core_impl/operations/printimpl/print_freestanding_cxx26.h
@@ -1,5 +1,7 @@
 #pragma once
 
+#error "We do not recommend using this header file for the time being."
+
 namespace fast_io
 {
 
diff --git a/include/fast_io_hosted/filesystem/dos_at.h b/include/fast_io_hosted/filesystem/dos_at.h
index e6ffd1bf2..a63ce23ba 100644
--- a/include/fast_io_hosted/filesystem/dos_at.h
+++ b/include/fast_io_hosted/filesystem/dos_at.h
@@ -17,6 +17,8 @@ extern int my_dos_rename(char const *oldname, char const *newname) noexcept __as
 // Because of limitations of MS-DOS, this function doesn't really link two files together.
 // However, it simulates a real link by copying the file at exists to new.
 extern int my_dos_link(char const *exists, char const *newname) noexcept __asm__("_link");
+// The symlink of djgpp only generates a 510-byte file and does not exist as a soft link, so it
+// will be disabled later.
 extern int my_dos_symlink(char const *exists, char const *newname) noexcept __asm__("_symlink");
 extern int my_dos_chmod(char const *path, mode_t mode) noexcept __asm__("_chmod");
 extern int my_dos_utime(char const *file, utimbuf const *time) noexcept __asm__("_utime");
@@ -136,9 +138,13 @@ inline auto dos22_api_dispatcher(int olddirfd, char const *oldpath, int newdirfd
 	}
 }
 
-inline void dos_symlinkat_impl(char const *oldpath, int newdirfd, char const *newpath)
+inline void dos_symlinkat_impl([[maybe_unused]] char const *oldpath, [[maybe_unused]] int newdirfd, [[maybe_unused]] char const *newpath)
 {
+#if defined(FAST_IO_USE_DJGPP_SYMLINK)
 	::fast_io::system_call_throw_error(::fast_io::posix::my_dos_symlink(oldpath, ::fast_io::details::my_dos_concat_tlc_path(newdirfd, newpath).c_str()));
+#else
+	throw_posix_error(ENOSYS);
+#endif
 }
 
 template <posix_api_12 dsp, typename... Args>
@@ -203,7 +209,6 @@ inline
 		[[fallthrough]];
 	case utime_flags::omit:
 		throw_posix_error(EINVAL);
-		::fast_io::unreachable();
 	default:
 		return ::fast_io::details::unix_timestamp_to_time_t(opt.timestamp);
 	}
diff --git a/include/fast_io_hosted/filesystem/nt_at.h b/include/fast_io_hosted/filesystem/nt_at.h
index 409e9ce66..75ca4f4fb 100644
--- a/include/fast_io_hosted/filesystem/nt_at.h
+++ b/include/fast_io_hosted/filesystem/nt_at.h
@@ -434,8 +434,9 @@ struct nt_create_nothrow_callback
 };
 
 template <bool zw>
-inline void nt_symlinkat_impl(char16_t const *oldpath_c_str, ::std::size_t oldpath_size,
-							  void *newdirhd, char16_t const *newpath_c_str, ::std::size_t newpath_size, bool kernel)
+inline void nt_symlinkat_impl([[maybe_unused]] char16_t const *oldpath_c_str, [[maybe_unused]] ::std::size_t oldpath_size,
+							  [[maybe_unused]] void *newdirhd, [[maybe_unused]] char16_t const *newpath_c_str, 
+                              [[maybe_unused]] ::std::size_t newpath_size, [[maybe_unused]] bool kernel)
 {
 #if !defined(_WIN32_WINNT) || _WIN32_WINNT > 0x0600
 
@@ -634,6 +635,7 @@ inline void nt_symlinkat_impl(char16_t const *oldpath_c_str, ::std::size_t oldpa
 		throw_nt_error(status);
 	}
 #else
+#if defined(FAST_IO_USE_DJGPP_SYMLINK)
 	constexpr nt_open_mode symbol_mode{::fast_io::win32::nt::details::calculate_nt_open_mode({::fast_io::open_mode::out, static_cast<perms>(436)})};
 
 	::fast_io::basic_nt_family_file<(zw ? nt_family::zw : nt_family::nt), char8_t> new_file(
@@ -647,6 +649,9 @@ inline void nt_symlinkat_impl(char16_t const *oldpath_c_str, ::std::size_t oldpa
 													 u8"\nThis is just a text to force symlink file to be 510 bytes long. Do not delete it nor spaces following it.");
 
 	::fast_io::operations::write_all(new_file, buffer, buffer + 510);
+#else
+	throw_nt_error(0xC0000002);
+#endif
 #endif
 }
 
@@ -824,7 +829,7 @@ inline auto nt_deal_with1x(void *dir_handle, path_type const &path, Args... args
 {
 	return nt_api_common(
 		path, [&](char16_t const *path_c_str, ::std::size_t path_size) {
-			return nt1x_api_dispatcher<family == nt_family::zw, dsp>(dir_handle, path_c_str, path_size, args...);
+			return nt1x_api_dispatcher < family == nt_family::zw, dsp > (dir_handle, path_c_str, path_size, args...);
 		});
 }
 
@@ -837,7 +842,7 @@ inline auto nt_deal_with12(old_path_type const &oldpath, void *newdirfd, new_pat
 		[&](char16_t const *oldpath_c_str, ::std::size_t oldpath_size) {
 			return nt_api_common(
 				newpath, [&](char16_t const *newpath_c_str, ::std::size_t newpath_size) {
-					return nt12_api_dispatcher<family == nt_family::zw, dsp>(oldpath_c_str, oldpath_size, newdirfd, newpath_c_str, newpath_size, args...);
+					return nt12_api_dispatcher < family == nt_family::zw, dsp > (oldpath_c_str, oldpath_size, newdirfd, newpath_c_str, newpath_size, args...);
 				});
 		});
 }
@@ -849,8 +854,8 @@ inline auto nt_deal_with22(void *olddirhd, oldpath_type const &oldpath, void *ne
 						 [&](char16_t const *oldpath_c_str, ::std::size_t oldpath_size) {
 							 return nt_api_common(newpath,
 												  [&](char16_t const *newpath_c_str, ::std::size_t newpath_size) {
-													  return nt22_api_dispatcher<family == nt_family::zw, dsp>(olddirhd, oldpath_c_str, oldpath_size, newdirhd,
-																											   newpath_c_str, newpath_size, args...);
+													  return nt22_api_dispatcher < family == nt_family::zw, dsp > (olddirhd, oldpath_c_str, oldpath_size, newdirhd,
+																												   newpath_c_str, newpath_size, args...);
 												  });
 						 });
 }
diff --git a/include/fast_io_hosted/filesystem/win32_9xa_at.h b/include/fast_io_hosted/filesystem/win32_9xa_at.h
index 074f66fdc..6146cc229 100644
--- a/include/fast_io_hosted/filesystem/win32_9xa_at.h
+++ b/include/fast_io_hosted/filesystem/win32_9xa_at.h
@@ -305,9 +305,11 @@ inline void win32_9xa_utimensat_impl(::fast_io::win32_9xa_dir_handle const &dirh
 	}
 }
 
-inline void win32_9xa_symlinkat_impl(char8_t const *oldpath_c_str, ::std::size_t oldpath_size,
-									 ::fast_io::win32_9xa_dir_handle const &newdirhd, char8_t const *newpath_c_str, ::std::size_t newpath_size)
+inline void win32_9xa_symlinkat_impl([[maybe_unused]] char8_t const *oldpath_c_str, [[maybe_unused]] ::std::size_t oldpath_size,
+									 [[maybe_unused]] ::fast_io::win32_9xa_dir_handle const &newdirhd, 
+                                     [[maybe_unused]] char8_t const *newpath_c_str, [[maybe_unused]] ::std::size_t newpath_size)
 {
+#if defined(FAST_IO_USE_DJGPP_SYMLINK)
 	::fast_io::containers::basic_cstring_view<char8_t> path{::fast_io::containers::null_terminated, oldpath_c_str, oldpath_size};
 
 	::fast_io::u8win32_file_9xa f{::fast_io::win32::details::basic_win32_9xa_create_file_at_fs_dirent_impl(
@@ -321,6 +323,10 @@ inline void win32_9xa_symlinkat_impl(char8_t const *oldpath_c_str, ::std::size_t
 	::fast_io::operations::print_freestanding<false>(u8obv, u8"!<symlink>", path, u8"\nThis is just a text to force symlink file to be 510 bytes long. Do not delete it nor spaces following it.");
 
 	::fast_io::operations::write_all(f, buffer, buffer + 510);
+
+#else 
+	throw_win32_error(0x1);
+#endif
 }
 
 inline void win32_9xa_linkat_impl(::fast_io::win32_9xa_dir_handle const &olddirhd, char8_t const *oldpath_c_str, ::std::size_t oldpath_size,
diff --git a/include/fast_io_hosted/platforms/win32/msvc_linker_32.h b/include/fast_io_hosted/platforms/win32/msvc_linker_32.h
index 0279ddbbf..a0e312070 100644
--- a/include/fast_io_hosted/platforms/win32/msvc_linker_32.h
+++ b/include/fast_io_hosted/platforms/win32/msvc_linker_32.h
@@ -1,4 +1,4 @@
-#pragma once
+#pragma once
 // This file have been generated by example/0039.win32mangling, therefore, do NOT edit this file directely!
 // clang-format off
 // WIN32
diff --git a/include/fast_io_hosted/platforms/win32/msvc_linker_32_i686.h b/include/fast_io_hosted/platforms/win32/msvc_linker_32_i686.h
index e7a26e1b4..a8493d1ba 100644
--- a/include/fast_io_hosted/platforms/win32/msvc_linker_32_i686.h
+++ b/include/fast_io_hosted/platforms/win32/msvc_linker_32_i686.h
@@ -1,4 +1,4 @@
-#pragma once
+#pragma once
 // This file have been generated by example/0039.win32mangling, therefore, do NOT edit this file directely!
 // clang-format off
 // WIN32
diff --git a/include/fast_io_hosted/platforms/win32/msvc_linker_64.h b/include/fast_io_hosted/platforms/win32/msvc_linker_64.h
index 39a9af191..184427533 100644
--- a/include/fast_io_hosted/platforms/win32/msvc_linker_64.h
+++ b/include/fast_io_hosted/platforms/win32/msvc_linker_64.h
@@ -1,4 +1,4 @@
-#pragma once
+#pragma once
 // This file have been generated by example/0039.win32mangling, therefore, do NOT edit this file directely!
 // clang-format off
 // WIN32
diff --git a/include/fast_io_hosted/platforms/win32/msvc_linker_arm64ec.h b/include/fast_io_hosted/platforms/win32/msvc_linker_arm64ec.h
index 2cb5c6159..262482bb7 100644
--- a/include/fast_io_hosted/platforms/win32/msvc_linker_arm64ec.h
+++ b/include/fast_io_hosted/platforms/win32/msvc_linker_arm64ec.h
@@ -1,4 +1,4 @@
-#pragma once
+#pragma once
 // This file have been generated by example/0039.win32mangling, therefore, do NOT edit this file directely!
 // clang-format off
 // WIN32