X-Git-Url: http://g0dil.de/git?a=blobdiff_plain;f=Utils%2FLogger%2FMainpage.dox;h=7a5509d6599d071c910cbc40c474ce24888f1269;hb=412024ed31a4ab4eaea7a4165a434f8efebee325;hp=f30c1fb054568ecef8f30b1d9045c813fd434246;hpb=61419d9a2e1060f7ede22fa19fd9d0b401bbc87a;p=senf.git diff --git a/Utils/Logger/Mainpage.dox b/Utils/Logger/Mainpage.dox index f30c1fb..7a5509d 100644 --- a/Utils/Logger/Mainpage.dox +++ b/Utils/Logger/Mainpage.dox @@ -1,8 +1,8 @@ // $Id$ // -// Copyright (C) 2007 -// Fraunhofer Institut fuer offene Kommunikationssysteme (FOKUS) -// Kompetenzzentrum fuer Satelitenkommunikation (SatCom) +// Copyright (C) 2007 +// Fraunhofer Institute for Open Communication Systems (FOKUS) +// Competence Center NETwork research (NET), St. Augustin, GERMANY // Stefan Bund // // This program is free software; you can redistribute it and/or modify @@ -32,7 +32,47 @@ \see \ref logging \n \ref config \n - + \ref targets \n + \ref loglevels + + \section logging_concepts Concepts + + Log messages are arbitrarily created throughout the code using simple log statements (which are + macros). Besides the log message itself, every log message is labeled with additional + information: The \e stream, the \e area and a log \e level. If the message is not compile-time + disabled, the message is then directed to one or several log \e targets. + + A \e stream combines log messages with a single purpose: Debug messages, access logging and so + on. Any number of streams may be defined. There is one predefined default stream called \c + senf::log::Debug. (see: \ref SENF_LOG_DEFINE_STREAM) + + The \e area gives information about the source location of the message. Areas may be defined and + assigned arbitrarily but should be used to label messages from a single class or subsystem. It + is possible to reuse a class as it's own area tag, which is often desireable. There is a + default area \c senf::log::DefaultArea which is used, when no other area is assigned. (see: \ref + SENF_LOG_DEFINE_AREA, \ref SENF_LOG_CLASS_AREA) + + The log \e level gives information on the importance of the message. The list of log-levels is + fixed. (see: \ref loglevels) + + Depending on their the \e stream, \e area and \e level information, log messages can be enabled + or disabled at \e compile time. Messages disabled at compile time should not generate any + code. (see: \ref SENF_LOG_CONF) + + \attention The default log stream senf::log::Debug has senf::log::VERBOSE messages + disabled at compile time. senf::log::VERBOSE message will therefore only appear, + if you explictly enable the messages for the area in question using (here for the area + some::Area) + 
 
+        g++ ... -DSENF_LOG_CONF="(( (senf)(log)(Debug), (some)(Area), VERBOSE ))" 
+
+ in addition to routing the messages at runtime. For more, see \ref config. + + To be of any use, the log messages have to be written somewhere. This is the responsibility of + any number of \e targets. A \e target receives messages and using it's routing information + decides, wether the message is output or not. A message may be routed to multiple targets + simultaneously or may not be output by any target at all. (see: \ref targets) + \section logging_tutorial Tutorial introduction Using the logging library mostly concerns using \ref SENF_LOG statements in your code. There are @@ -43,23 +83,22 @@ // Define a new log stream with default level, runtime limit and compile time limit // set to senf::log::MESSAGE - SENF_LOG_DEF_STREAM( UserLog, senf::log::MESSAAGE, senf::log::MESSAGE, senf::log::MESSAGE ); + SENF_LOG_DEFINE_STREAM( UserLog, senf::log::MESSAGE, senf::log::MESSAGE, senf::log::MESSAGE ); class Froblizer { // Define a log area which will automatically be used by all members of this class. - // This is a combination of SENF_LOG_DEF_AREA and SENF_LOG_DEFAULT_AREA. + // This is a combination of SENF_LOG_DEFINE_AREA and SENF_LOG_DEFAULT_AREA. SENF_LOG_CLASS_AREA(); - // Set default log parameters for this scope. The values here are not really - // necessary since these are the global default values + // Set default log parameters for this scope. SENF_LOG_DEFAULT_STREAM(foo::UserLog); SENF_LOG_DEFAULT_LEVEL(senf::log::NOTICE); // Define an alias for emergency debug messages // The log area is inherited from the default at the place, where this // alias is used *not* where it is defined - SENF_LOG_DEF_ALIAS(LogEmerg, (senf::log::Debug)(senf::log::CRITICAL)); + SENF_LOG_DEFINE_ALIAS(LogEmerg, (senf::log::Debug)(senf::log::CRITICAL)); void test(); @@ -71,7 +110,7 @@ void foo::Froblizer::froblize() { SENF_LOG(("This is the UserLog at level NOTICE in the FroblizeArea")); - SENF_LOG((senf::log::WARNING) ("Same stream and area but at warning level")); + SENF_LOG((senf::log::IMPORTANT) ("Same stream and area but at important level")); SENF_LOG((LogEmerg) ("This goes to the DebugLog at level CRITICAL in the FroblizerArea")); } @@ -83,15 +122,29 @@ SENF_LOG(("Log to UserLog stream in Froblizer area however at VERBOSE level")); } + + int main(int, char **) + { + // Set up the routing targets + senf::log::ConsoleTarget & console (senf::log::ConsoleTarget::instance()); + senf::log::FileTarget logfile ("my.log"); + + // Debug messages go to the console + console.route(); + // Important user message are written to the log file + logfile.route(); + } \endcode \implementation I would have much preferred a more C++ like implementation. However given the design goals \li Flexible configuration at compile and runtime \li Concise usage and simple interface - \li Zero overhead for compile-time disabled log messages I did not find any non-mcaro - implementation which was not either completely convoluted, unusable or slow. So I turned to - a macro based implementation which can provide all the design goals stated above. + \li Zero overhead for compile-time disabled log messages + + I did not find any non-mcaro implementation which was not either completely convoluted, + unusable or slow. So I turned to a macro based implementation which can provide all the + design goals stated above. */