Differences

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--- tools:logger:start [2020/11/26 13:03] – [Log Levels] ursgraf
+++ tools:logger:start [2026/04/13 11:12] (current) – [Adding Output to the SysLog] ursgraf
@@ Line 37: / Line 37: @@
 <code cpp>
-  StreamLogWriter w(std::cout);
+  Logger::setDefaultStreamLogger(std::cout);
-  Logger::setDefaultWriter(&w);
+  Logger log = Logger::getLogger();  // this logger will output onto the default ''LogWriter''.
-  Logger log;  // this logger will output onto the default ''LogWriter''.
 </code>
 If you forget to assign a default logger, you will not get logging information from components of the library such as the safety system or the executor.
@@ Line 46: / Line 45: @@
 Sometimes it can be desirable to have a logger write to the console and write the same content into a file. This is especially helpful on a embedded system where you start an application remotely (e.g. through //ssh//). In such a case you can define a ''StreamLogWriter'' as follows:
 <code cpp>
-  StreamLogWriter w(std::cout, "/tmp/log");
+  Logger::setDefaultStreamLogger(std::cout, "/tmp/log");
+</code>
+A log file will be created at the given location. Its file name will be appended with the current date and time of the creation of the file.
+===== Adding Output to the SysLog =====
+The simplest way to attach a second sink is via Logger::addWriter(), which promotes the existing writer into a MultiLogWriter automatically:
+<code cpp>
+  Logger::setDefaultStreamLogger(std::cout, "/tmp/myLog");
+  Logger::addWriter(std::make_shared<SysLogWriter>("myLog"));
+  auto log = Logger::getLogger('A');
+  log.show(LogLevel::INFO);  // propagates to both sinks
+</code>
+Alternatively, build the MultiLogWriter explicitly before any getLogger()
+call and hand it to Logger::setDefaultWriter():
+<code cpp>
+  #include <eeros/logger/MultiLogWriter.hpp>
+  auto multi = std::make_shared<MultiLogWriter>();
+  multi->add(std::make_shared<StreamLogWriter>(std::cout, "/tmp/myLog"));
+  multi->add(std::make_shared<SysLogWriter>("myLog"));
+  Logger::setDefaultWriter(multi);
+</code>
+View the produced log entries in the system log with
+<code bash>
+$ journalctl -t myLog
 </code>
-A lop file will be created at the given location. Its file name will be appended with the current date and time of the creation of the file. That is the creation of the ''StreamLogWriter'' object.