diff options
| author | Klaus Schmidinger <vdr@tvdr.de> | 2017-04-02 13:01:34 +0200 |
|---|---|---|
| committer | Klaus Schmidinger <vdr@tvdr.de> | 2017-04-02 13:01:34 +0200 |
| commit | fe535d25e58d75397ddefeb796bf60e897360f35 (patch) | |
| tree | cca4c3473ce265003c4147b98d0c48a9b95c8385 | |
| parent | c4cc5e613ccfbf573a7ed66d17702581ef00e376 (diff) | |
| download | vdr-fe535d25e58d75397ddefeb796bf60e897360f35.tar.gz vdr-fe535d25e58d75397ddefeb796bf60e897360f35.tar.bz2 | |
Added some guidelines and recommendations to the 'Logging' section of PLUGINS.html
| -rw-r--r-- | HISTORY | 4 | ||||
| -rw-r--r-- | PLUGINS.html | 24 |
2 files changed, 28 insertions, 0 deletions
@@ -8944,3 +8944,7 @@ Video Disk Recorder Revision History store auxiliary information with an event (thanks to J�rg Wendel). This string has no meaning whatsoever to VDR itself, and it will not be written into the info file of a recording that is made for such an event. +- Added some guidelines and recommendations to the 'Logging' section of PLUGINS.html. + The most important being: implement a command line option to control the level + of logging (in particular allow turning off logging completely!) and never print + anything to stdout or stderr (unless one of the listed exceptions applies). diff --git a/PLUGINS.html b/PLUGINS.html index dd7a154f..92a4d313 100644 --- a/PLUGINS.html +++ b/PLUGINS.html @@ -583,6 +583,30 @@ esyslog("pluginname: error #%d has occurred", ErrorNumber); Note that the log messages will be given as provided, the plugin's name will not automatically be added, so make sure your log messages are obvious enough. +<p> +<modified> +Only use the above logging functions for occasional log messages. Do not use +them unconditionally for frequent messages that produce long sequences of lines +in the log file every few seconds. That might make it hard to work on other plugins +or the core VDR code, watching their log entries while they are permanently +interspersed with unrelated stuff.<br> +<br> +The recommended behavior for a plugin that does logging is to implement a command +line option that controls the level of log messages, preferably '-l N, --log=N', +where 'N' is in the range 0...3, with 0 meaning no logging whatsoever, 1 log only +errors, 2 log errors and informational messages, and 3 also log debug information.<br> +<br> +If a plugin can output extensive data for special debugging purposes (either to +the log file or stdout/stderr), this should be enabled by setting proper switches +in one of its source files (see for example how the communication between VDR and +CAMs can be monitored in VDR/ci.c).<br> +<br> +Under no circumstances must a plugin print anything to stdout or stderr during +normal operation! The only exceptions being special debug information as described +above, fatal error messages that will cause VDR to abort, or if it is the sole +purpose of the plugin to display something on stdout, like for instance the +<i>skincurses</i> plugin, which displays the OSD at the console. +</modified> <hr><h2><a name="Main menu entry">Main menu entry</a></h2> |