diff --git a/NuFX/nufx_error.cpp b/NuFX/nufx_error.cpp
new file mode 100644
index 0000000..ab1796a
--- /dev/null
+++ b/NuFX/nufx_error.cpp
@@ -0,0 +1,48 @@
+#include "nufx_error.h"
+#include <string>
+
+namespace {
+	class private_error_category : public std::error_category {
+
+		virtual std::error_condition default_error_condition( int code ) const noexcept;
+		virtual std::string message( int condition ) const noexcept;
+		virtual const char* name() const noexcept;
+	};
+
+	std::error_condition private_error_category::default_error_condition( int code ) const noexcept
+	{
+
+		switch(code)
+		{
+		case kNuErrInvalidArg:
+			return std::errc::invalid_argument;
+		case kNuErrMalloc:
+			return std::errc::not_enough_memory;
+		case kNuErrFileNotFound:
+			return std::errc::no_such_file_or_directory;
+		case kNuErrNotDir:
+			return std::errc::not_a_directory;
+		case kNuErrFileAccessDenied:
+			return std::errc::permission_denied;
+			
+		default:
+			return std::error_condition(code, *this);
+		}
+	}
+
+	const char* private_error_category::name() const noexcept
+	{
+		return "NuFX Error";
+	}
+	std::string private_error_category::message( int condition ) const noexcept
+	{
+		return NuStrError((NuError)condition);
+	}
+
+}
+
+std::error_category &nufx_category()
+{
+	static private_error_category ec;
+	return ec;	
+}
diff --git a/NuFX/nufx_error.h b/NuFX/nufx_error.h
new file mode 100644
index 0000000..f310a15
--- /dev/null
+++ b/NuFX/nufx_error.h
@@ -0,0 +1,28 @@
+#ifndef __nufx_error__
+#define __nufx_error__
+
+
+#include <system_error>
+#include <NufxLib.h>
+
+	std::error_category &nufx_category();
+
+namespace std {
+
+	template<>
+	struct is_error_code_enum<NuError> : public true_type {};
+
+}
+
+// hmm... this should not be in a namespace.
+inline std::error_condition make_error_condition(NuError e)
+{
+	
+	// positive values are posix errors.
+	return e < 0
+		? std::error_condition(e, nufx_category());
+		: std::error_condition(e, std::system_category());
+}
+
+
+#endif