diff --git a/repos/base/include/log_session/client.h b/repos/base/include/log_session/client.h
index ee96a120ad..4721d4aefc 100644
--- a/repos/base/include/log_session/client.h
+++ b/repos/base/include/log_session/client.h
@@ -25,8 +25,7 @@ struct Genode::Log_session_client : Rpc_client<Log_session>
 	explicit Log_session_client(Log_session_capability session)
 	: Rpc_client<Log_session>(session) { }
 
-	size_t write(String const &string) override {
-		return call<Rpc_write>(string); }
+	void write(String const &string) override { call<Rpc_write>(string); }
 };
 
 #endif /* _INCLUDE__LOG_SESSION__CLIENT_H_ */
diff --git a/repos/base/include/log_session/log_session.h b/repos/base/include/log_session/log_session.h
index 3551e45a99..5c7969824a 100644
--- a/repos/base/include/log_session/log_session.h
+++ b/repos/base/include/log_session/log_session.h
@@ -50,17 +50,15 @@ struct Genode::Log_session : Session
 
 	/**
 	 * Output null-terminated string
-	 *
-	 * \return  number of written characters
 	 */
-	virtual size_t write(String const &string) = 0;
+	virtual void write(String const &string) = 0;
 
 
 	/*********************
 	 ** RPC declaration **
 	 *********************/
 
-	GENODE_RPC(Rpc_write, size_t, write, String const &);
+	GENODE_RPC(Rpc_write, void, write, String const &);
 	GENODE_RPC_INTERFACE(Rpc_write);
 };
 
diff --git a/repos/base/src/core/include/log_session_component.h b/repos/base/src/core/include/log_session_component.h
index 29bda822cc..2271d37ab2 100644
--- a/repos/base/src/core/include/log_session_component.h
+++ b/repos/base/src/core/include/log_session_component.h
@@ -49,15 +49,15 @@ namespace Genode {
 			 ** Log session **
 			 *****************/
 
-			size_t write(String const &string_buf) override
+			void write(String const &string_buf) override
 			{
 				if (!(string_buf.valid_string())) {
 					error("corrupted string");
-					return 0;
+					return;
 				}
 
-				char const *string = string_buf.string();
-				size_t len = strlen(string);
+				char const * const string = string_buf.string();
+				size_t const len = strlen(string);
 
 				unsigned from_i = 0;
 				for (unsigned i = 0; i < len; i++) {
@@ -70,8 +70,6 @@ namespace Genode {
 				/* if last character of string was not a line break, add one */
 				if (from_i < len)
 					log(_label, Cstring(string + from_i));
-
-				return len;
 			}
 	};
 }
diff --git a/repos/base/src/lib/base/default_log.cc b/repos/base/src/lib/base/default_log.cc
index 2da61f31bb..598dd457b5 100644
--- a/repos/base/src/lib/base/default_log.cc
+++ b/repos/base/src/lib/base/default_log.cc
@@ -40,7 +40,7 @@ namespace {
 		Back_end(Parent &parent)
 		: _client(reinterpret_cap_cast<Log_session>(_cap(parent))) { }
 
-		void write(char const *string) { (void)_client.write(string); }
+		void write(char const *string) { _client.write(string); }
 	};
 }
 
diff --git a/repos/demo/src/server/nitlog/main.cc b/repos/demo/src/server/nitlog/main.cc
index 77c52539de..390b1fec51 100644
--- a/repos/demo/src/server/nitlog/main.cc
+++ b/repos/demo/src/server/nitlog/main.cc
@@ -302,15 +302,14 @@ class Nitlog::Session_component : public Rpc_object<Log_session>
 		 ** Log session interface **
 		 ***************************/
 
-		size_t write(String const &log_text) override
+		void write(String const &log_text) override
 		{
 			if (!log_text.valid_string()) {
 				error("corrupted string");
-				return 0;
+				return;
 			}
 
 			_log_window.write(_color, _label.string(), log_text.string(), _id);
-			return strlen(log_text.string());
 		}
 };
 
diff --git a/repos/gems/src/app/depot_autopilot/main.cc b/repos/gems/src/app/depot_autopilot/main.cc
index 3abd1afbfb..33da2bd625 100644
--- a/repos/gems/src/app/depot_autopilot/main.cc
+++ b/repos/gems/src/app/depot_autopilot/main.cc
@@ -46,9 +46,9 @@ class Depot_deploy::Log_session_component : public Rpc_object<Log_session>
 			_child(child)
 		{ }
 
-		size_t write(String const &line) override
+		void write(String const &line) override
 		{
-			return _child.log_session_write(line, _label);
+			_child.log_session_write(line, _label);
 		}
 };
 
diff --git a/repos/libports/src/test/libc_component/main.cc b/repos/libports/src/test/libc_component/main.cc
index 0cb224df0e..7338676fce 100644
--- a/repos/libports/src/test/libc_component/main.cc
+++ b/repos/libports/src/test/libc_component/main.cc
@@ -173,9 +173,9 @@ struct Log::Session_component : Genode::Rpc_object<Log_session>
 		_read(); _read();
 	}
 
-	Genode::size_t write(String const &string_buf)
+	void write(String const &string_buf) override
 	{
-		if (!(string_buf.valid_string())) { return 0; }
+		if (!(string_buf.valid_string())) { return; }
 
 		strncpy(_buf, string_buf.string(), sizeof(_buf));
 		size_t len = strlen(_buf);
@@ -185,8 +185,6 @@ struct Log::Session_component : Genode::Rpc_object<Log_session>
 		Genode::log("RPC with \"", Genode::Cstring(_buf), "\"");
 
 		_select();
-
-		return len;
 	}
 };
 
diff --git a/repos/os/src/app/dummy/main.cc b/repos/os/src/app/dummy/main.cc
index b44dee4f8a..145e169c59 100644
--- a/repos/os/src/app/dummy/main.cc
+++ b/repos/os/src/app/dummy/main.cc
@@ -61,7 +61,7 @@ struct Dummy::Log_service
 				log("closing session with label ", _label);
 		}
 
-		size_t write(String const &string) override
+		void write(String const &string) override
 		{
 			/* strip known line delimiter from incoming message */
 			unsigned n = 0;
@@ -71,8 +71,6 @@ struct Dummy::Log_service
 			typedef Genode::String<100> Message;
 			Message const message("[", _label, "] ", Cstring(string.string(), n));
 			log(message);
-
-			return strlen(string.string());
 		}
 	};
 
diff --git a/repos/os/src/server/fs_log/session.h b/repos/os/src/server/fs_log/session.h
index 1608dcc927..b2d4e5172f 100644
--- a/repos/os/src/server/fs_log/session.h
+++ b/repos/os/src/server/fs_log/session.h
@@ -76,13 +76,13 @@ class Fs_log::Session_component : public Genode::Rpc_object<Genode::Log_session>
 		 ** Log session **
 		 *****************/
 
-		Genode::size_t write(Log_session::String const &msg) override
+		void write(Log_session::String const &msg) override
 		{
 			using namespace Genode;
 
 			if (!msg.valid_string()) {
 				Genode::error("received corrupted string");
-				return 0;
+				return;
 			}
 
 			size_t msg_len = strlen(msg.string());
@@ -123,7 +123,6 @@ class Fs_log::Session_component : public Genode::Rpc_object<Genode::Log_session>
 			memcpy(buf, msg.string(), msg_len);
 
 			source.submit_packet(packet);
-			return msg_len;
 		}
 };
 
diff --git a/repos/os/src/server/terminal_log/main.cc b/repos/os/src/server/terminal_log/main.cc
index 991abc10a8..e1bc6c2799 100644
--- a/repos/os/src/server/terminal_log/main.cc
+++ b/repos/os/src/server/terminal_log/main.cc
@@ -52,11 +52,11 @@ namespace Genode {
 			 * The following function's code is a modified variant of the one in:
 			 * 'base/src/core/include/log_session_component.h'
 			 */
-			size_t write(String const &string_buf) override
+			void write(String const &string_buf) override
 			{
 				if (!(string_buf.valid_string())) {
 					Genode::error("corrupted string");
-					return 0;
+					return;
 				}
 
 				char const *string = string_buf.string();
@@ -73,7 +73,7 @@ namespace Genode {
 				enum { ESC = 27 };
 				if ((string[0] == ESC) && (len == 5) && (string[4] == '\n')) {
 					_terminal.write(string, len - 1);
-					return len;
+					return;
 				}
 
 				_terminal.write(_label, strlen(_label));
@@ -85,8 +85,6 @@ namespace Genode {
 
 				/* carriage-return as expected by hardware terminals on newline */
 				_terminal.write("\r", 1);
-
-				return len;
 			}
 	};
 
diff --git a/repos/os/src/test/init/main.cc b/repos/os/src/test/init/main.cc
index c6a3f697ef..38436cc335 100644
--- a/repos/os/src/test/init/main.cc
+++ b/repos/os/src/test/init/main.cc
@@ -138,7 +138,7 @@ class Test::Log_session_component : public Rpc_object<Log_session>
 			_label(label), _handler(handler)
 		{ }
 
-		size_t write(String const &string) override
+		void write(String const &string) override
 		{
 			/* strip known line delimiter from incoming message */
 			unsigned n = 0;
@@ -153,8 +153,6 @@ class Test::Log_session_component : public Rpc_object<Log_session>
 				_handler.handle_log_message(message);
 
 			log(message, " (", result, ")");
-
-			return strlen(string.string());
 		}
 };
 
diff --git a/repos/os/src/test/sandbox/main.cc b/repos/os/src/test/sandbox/main.cc
index 122f330cee..c4120ddd06 100644
--- a/repos/os/src/test/sandbox/main.cc
+++ b/repos/os/src/test/sandbox/main.cc
@@ -31,13 +31,11 @@ struct Test::Log_session_component : Session_object<Log_session>
 	template <typename... ARGS>
 	Log_session_component(ARGS &&... args) : Session_object(args...) { }
 
-	size_t write(String const &msg) override
+	void write(String const &msg) override
 	{
 		/* omit line break and zero termination supplied by 'msg' */
 		if (msg.size() > 1)
 			log("local LOG service: ", Cstring(msg.string(), msg.size() - 2));
-
-		return 0;
 	}
 };