diff --git a/source/mijin/logging/debug_output_sink.hpp b/source/mijin/logging/debug_output_sink.hpp
new file mode 100644
index 0000000..54c900e
--- /dev/null
+++ b/source/mijin/logging/debug_output_sink.hpp
@@ -0,0 +1,67 @@
+
+#pragma once
+
+#if !defined(MIJIN_LOGGING_DEBUG_OUTPUT_SINK_HPP_INCLUDED)
+#define MIJIN_LOGGING_DEBUG_OUTPUT_SINK_HPP_INCLUDED 1
+
+#include "./formatting.hpp"
+#include "../detect.hpp"
+#include "../util/traits.hpp"
+
+#if MIJIN_TARGET_OS == MIJIN_OS_WINDOWS
+#pragma comment(lib, "Kernel32.lib")
+
+extern "C" void OutputDebugStringA(const char* lpOutputString);
+extern "C" void OutputDebugStringW(const wchar_t* lpOutputString);
+
+namespace mijin
+{
+template<MIJIN_FORMATTING_SINK_TMPL_ARGS_INIT>
+    requires(allocator_type<TAllocator<TChar>>)
+class BaseDebugOutputSink : public BaseFormattingLogSink<MIJIN_FORMATTING_SINK_TMP_ARG_NAMES>
+{
+public:
+    using base_t = BaseFormattingLogSink<MIJIN_FORMATTING_SINK_TMP_ARG_NAMES>;
+    using typename base_t::char_t;
+    using typename base_t::allocator_t;
+    using typename base_t::formatter_ptr_t;
+    using typename base_t::message_t;
+public:
+    explicit BaseDebugOutputSink(formatter_ptr_t formatter, allocator_t allocator = {})
+        MIJIN_NOEXCEPT_IF(std::is_nothrow_move_constructible_v<allocator_t>)
+            : base_t(std::move(formatter), std::move(allocator)) {}
+
+    void handleMessageFormatted(const message_t&, const char_t* formatted) MIJIN_NOEXCEPT override
+    {
+        if constexpr (std::is_same_v<char_t, char>)
+        {
+            OutputDebugStringA(formatted);
+            OutputDebugStringA("\n");
+        }
+        else if constexpr (std::is_same_v<char_t, wchar_t>)
+        {
+            OutputDebugStringW(formatted);
+            OutputDebugStringW(L"\n");
+        }
+        else if constexpr (sizeof(char_t) == sizeof(char))
+        {
+            // char8_t etc.
+            OutputDebugStringA(std::bit_cast<const char*>(formatted));
+            OutputDebugStringA("\n");
+        }
+        else
+        {
+            static_assert(always_false_v<char_t>, "Character type not supported.");
+        }
+    }
+};
+
+#define SINK_SET_ARGS(chr_type) chr_type, std::char_traits<chr_type>, TAllocator, TDeleter
+
+MIJIN_DEFINE_CHAR_VERSIONS_TMPL(DebugOutputSink, MIJIN_FORMATTING_SINK_COMMON_ARGS, SINK_SET_ARGS)
+
+#undef SINK_SET_ARGS
+} // namespace mijin
+
+#endif // MIJIN_TARGET_OS == MIJIN_OS_WINDOWS
+#endif // !defined(MIJIN_LOGGING_DEBUG_OUTPUT_SINK_HPP_INCLUDED)
diff --git a/source/mijin/logging/formatting.hpp b/source/mijin/logging/formatting.hpp
index ad3a6f8..cae956d 100644
--- a/source/mijin/logging/formatting.hpp
+++ b/source/mijin/logging/formatting.hpp
@@ -92,10 +92,10 @@ public:
     using string_t = formatter_t::string_t;
     using typename base_t::message_t;
 private:
-    not_null_t<formatter_ptr_t> mFormatter;
+    formatter_ptr_t mFormatter;
     string_t mBuffer;
 public:
-    explicit BaseFormattingLogSink(not_null_t<formatter_ptr_t> formatter, allocator_t allocator = {})
+    explicit BaseFormattingLogSink(formatter_ptr_t formatter, allocator_t allocator = {})
         MIJIN_NOEXCEPT_IF(std::is_nothrow_move_constructible_v<allocator_t>)
         : mFormatter(std::move(formatter)), mBuffer(std::move(allocator))
     {}
diff --git a/source/mijin/logging/logger.hpp b/source/mijin/logging/logger.hpp
index 4904ae7..5de4045 100644
--- a/source/mijin/logging/logger.hpp
+++ b/source/mijin/logging/logger.hpp
@@ -254,10 +254,14 @@ MIJIN_DEFINE_LOG_LEVEL(ERROR, MIJIN_LOG_LEVEL_VALUE_ERROR)
 #define MIJIN_LOG_ALWAYS(level, channel, ...) MIJIN_FUNCNAME_GET_LOGGER().log(                                     \
     MIJIN_LOG_LEVEL_OBJECT(level), MIJIN_LOG_CHANNEL_OBJECT(channel), std::source_location::current(), __VA_ARGS__ \
 )
-#define MIJIN_LOG(level, channel, ...)                                                    \
+#define MIJIN_LOG(level, channel, ...)                                                         \
 if constexpr (MIJIN_LOG_LEVEL_OBJECT(level).value < MIJIN_FUNCNAME_MIN_LOG_LEVEL_COMPILE()) {} \
 else MIJIN_LOG_ALWAYS(level, channel, __VA_ARGS__)
 
+#define MIJIN_LOG_IF(cond, level, channel, ...)                                                \
+if constexpr (MIJIN_LOG_LEVEL_OBJECT(level).value < MIJIN_FUNCNAME_MIN_LOG_LEVEL_COMPILE()) {} \
+else if (cond) MIJIN_LOG_ALWAYS(level, channel, __VA_ARGS__)
+
 #define MIJIN_SET_CLASS_LOGGER(loggerExpr)             \
 const auto& MIJIN_FUNCNAME_GET_LOGGER() const noexcept \
 {                                                      \
@@ -268,6 +272,11 @@ auto MIJIN_FUNCNAME_GET_LOGGER = [&]() -> const auto& \
 {                                                     \
     return loggerExpr;                                \
 };
+#define MIJIN_SET_NS_LOGGER(loggerExpr)                 \
+inline const mijin::Logger& MIJIN_FUNCNAME_GET_LOGGER() \
+{                                                       \
+    return loggerExpr;                                  \
+}
 #define MIJIN_SET_CLASS_MIN_LOG_LEVEL_COMPILE(level)      \
 int MIJIN_FUNCNAME_MIN_LOG_LEVEL_COMPILE() MIJIN_NOEXCEPT \
 {                                                         \
diff --git a/source/mijin/logging/stdio_sink.hpp b/source/mijin/logging/stdio_sink.hpp
index 7aa1e8c..423806a 100644
--- a/source/mijin/logging/stdio_sink.hpp
+++ b/source/mijin/logging/stdio_sink.hpp
@@ -22,7 +22,7 @@ public:
 private:
     int mMinStderrLevel = MIJIN_LOG_LEVEL_VALUE_WARNING;
 public:
-    explicit BaseStdioSink(not_null_t<formatter_ptr_t> formatter, allocator_t allocator = {})
+    explicit BaseStdioSink(formatter_ptr_t formatter, allocator_t allocator = {})
         MIJIN_NOEXCEPT_IF(std::is_nothrow_move_constructible_v<allocator_t>)
         : base_t(std::move(formatter), std::move(allocator)) {}