A unix file descriptor streambuf for writing.

IOStreams/CMakeLists.txt

@@ -1,3 +1,4 @@
 add_subdirectory( IStreamable.test )
 add_subdirectory( OStreamable.test )
 add_subdirectory( streamable.test )
+add_subdirectory( OutUnixFileBuf.test )

IOStreams/OutUnixFileBuf.h

@@ -0,0 +1,47 @@
+static_assert( __cplusplus > 2020'99 );
+
+#pragma once
+
+#include <Alepha/Alepha.h>
+
+#include <unistd.h>
+
+#include <streambuf>
+
+namespace Alepha::Hydrogen::IOStreams  ::detail::  OutUnixFileBuf_m
+{
+	inline namespace exports
+	{
+		class OutUnixFileBuf;
+	}
+
+	class exports::OutUnixFileBuf
+		: virtual public std::streambuf
+	{
+		private:
+			int fd;
+
+			int
+			overflow( const int ch_ ) override
+			{
+				if( ch_ == EOF ) throw std::runtime_error{ "Unexpected EOF" };
+				const char ch= ch_;
+				xsputn( &ch, 1 );
+				return ch_;
+			}
+
+			std::streamsize
+			xsputn( const char *const data, const std::streamsize amt ) override
+			{
+				return ::write( fd, data, amt );
+			}
+
+		public:
+			explicit OutUnixFileBuf( const int fd ) : fd( fd ) {}
+	};
+}
+
+namespace Alepha::Hydrogen::IOStreams::inline exports::inline OutUnixFileBuf_m
+{
+	using namespace detail::OutUnixFileBuf_m::exports;
+}

IOStreams/OutUnixFileBuf.test/0.cc

@@ -0,0 +1,28 @@
+static_assert( __cplusplus > 2020'99 );
+
+#include "../OutUnixFileBuf.h"
+
+#include <Alepha/Testing/test.h>
+#include <Alepha/AutoRAII.h>
+
+#include <unistd.h>
+#include <fcntl.h>
+
+#include <Alepha/Utility/evaluation_helpers.h>
+
+auto init= Alepha::Utility::enroll <=[]
+{
+	using namespace Alepha::Testing::exports;
+
+	"Can we write to /dev/null?"_test <=[]
+	{
+		const auto fd= Alepha::AutoRAII
+		{
+			[]{ return open( "/dev/null", O_WRONLY ); },
+			::close
+		};
+
+		Alepha::IOStreams::OutUnixFileBuf buf{ fd };
+		std::ostream file{ &buf };
+	};
+};

IOStreams/OutUnixFileBuf.test/CMakeLists.txt

@@ -0,0 +1 @@
+unit_test( 0 )