Home Man
Search
Today's Posts
Register

Linux & Unix Commands - Search Man Pages

RedHat 9 (Linux i386) - man page for log (redhat section n)

log(n)					 Logging facility				   log(n)

NAME
       log - Procedures to log messages of libraries and applications.

SYNOPSIS
       package require Tcl 8

       package require log ?1.0.1?

       ::log::levels

       ::log::lv2longform level

       ::log::lv2color level

       ::log::lv2priority level

       ::log::lv2cmd level

       ::log::lv2channel level

       ::log::lvCompare level1 level2

       ::log::lvSuppress level {suppress 1}

       ::log::lvSuppressLE level {suppress 1}

       ::log::lvIsSuppressed level

       ::log::lvCmd level cmd

       ::log::lvCmdForall cmd

       ::log::lvChannel level chan

       ::log::lvChannelForall chan

       ::log::lvColor level color

       ::log::lvColorForall color

       ::log::log level text

       ::log::logMsg text

       ::log::logError text

       ::log::Puts level text

DESCRIPTION
       The log package provides commands that allow libraries and applications to selectively log
       information about their internal operation and state.

       To use the package just execute

	   package require log
	   log::log notice "Some message"

       As can be seen above, each message given to the log facility is associated  with  a  level
       determining  the  importance of the message. The user can then select which levels to log,
       what commands to use for the logging of each level and the channel to  write  the  message
       to. In the following example the logging of all message with level debug is deactivated.

	   package require log
	   log::lvSupress debug
	   log::log debug "Unseen message" ; # No output

       By  default  all  messages associated with an error-level (emergency, alert, critical, and
       error) are written to stderr. Messages with any other level are written to stdout. In  the
       following example the log module is reconfigured to write debug messages to stderr too.

	   package require log
	   log::lvChannel debug stderr
	   log::log debug "Written to stderr"

       Each  message  level  is also associated with a command to use when logging a message with
       that level. The behaviour above for example relies on the fact that all message levels use
       by  default  the standard command ::log::Puts to log any message. In the following example
       all messages of level notice are given to the non-standard  command  toText  for  logging.
       This  disables the channel setting for such messages, assuming that toText does not use it
       by itself.

	   package require log
	   log::lvCmd notice toText
	   log::log notice "Handled by

       Another database maintained by this facility is a map from message levels to  colors.  The
       information in this database has no influence on the behaviour of the module. It is merely
       provided as a convenience and in anticipation of the usage of this  facility  in  tk-based
       application which may want to colorize message logs.

API
       The following commands are available:

       ::log::levels
	      Returns the names of all known levels, in alphabetical order.

       ::log::lv2longform level
	      Converts any unique abbreviation of a level name to the full level name.

       ::log::lv2color level
	      Converts any level name including unique abbreviations to the corresponding color.

       ::log::lv2priority level
	      Converts	any level name including unique abbreviations to the corresponding prior-
	      ity.

       ::log::lv2cmd level
	      Converts any level name including unique abbreviations to the command  prefix  used
	      to write messages with that level.

       ::log::lv2channel level
	      Converts	any  level  name  including  unique  abbreviations to the channel used by
	      ::log::Puts to write messages with that level.

       ::log::lvCompare level1 level2
	      Compares two levels (including unique abbreviations) with respect to  their  prior-
	      ity. This command can be used by the -command option of lsort. The result is one of
	      -1, 0 or 1 or an error. A result of -1 signals that level1 is of less priority than
	      level2.  0  signals  that both levels have the same priority. 1 signals that level1
	      has higher priority than level2.

       ::log::lvSuppress level {suppress 1}]
	      (Un)suppresses the output of messages having the specified level. Unique	abbrevia-
	      tions for the level are allowed here too.

       ::log::lvSuppressLE level {suppress 1}]
	      (Un)suppresses  the  output of messages having the specified level or one of lesser
	      priority. Unique abbreviations for the level are allowed here too.

       ::log::lvIsSuppressed level
	      Asks the package whether the specified level is currently suppressed. Unique abbre-
	      viations of level names are allowed.

       ::log::lvCmd level cmd
	      Defines  for  the  specified  level with which command to write the messages having
	      this level. Unique abbreviations of level names are allowed. The command	is  actu-
	      ally  a command prefix and this facility will append 2 arguments before calling it,
	      the level of the message and the message itself, in this order.

       ::log::lvCmdForall cmd
	      Defines for all known levels with which command to write the messages  having  this
	      level.  The  command  is	actually a command prefix and this facility will append 2
	      arguments before calling it, the level of the message and the  message  itself,  in
	      this order.

       ::log::lvChannel level chan
	      Defines  for  the specified level into which channel ::log::Puts (the standard com-
	      mand) shall write the messages having this level.  Unique  abbreviations	of  level
	      names  are allowed. The command is actually a command prefix and this facility will
	      append 2 arguments before calling it, the level of  the  message	and  the  message
	      itself, in this order.

       ::log::lvChannelForall chan
	      Defines  for  all  known	levels with which which channel ::log::Puts (the standard
	      command) shall write the messages having this level. The command is actually a com-
	      mand  prefix and this facility will append 2 arguments before calling it, the level
	      of the message and the message itself, in this order.

       ::log::lvColor level color
	      Defines for the  specified  level  the  color  to  return  for  it  in  a  call  to
	      ::log::lv2color. Unique abbreviations of level names are allowed.

       ::log::lvColorForall color
	      Defines	for  all  known  levels  the  color  to  return  for  it  in  a  call  to
	      ::log::lv2color. Unique abbreviations of level names are allowed.

       ::log::log level text
	      Log a message according to the specifications for commands, channels  and  suppres-
	      sion.  In  other	words: The command will do nothing if the specified level is sup-
	      pressed. If it is not suppressed the actual logging is delegated to  the	specified
	      command.	If  there  is  no  command  specified  for the level the message won't be
	      logged. The standard command ::log::Puts will write  the	message  to  the  channel
	      specified for the given level. If no channel is specified for the level the message
	      won't be logged. Unique abbreviations of level names are	allowed.  Errors  in  the
	      actual  logging  command	are not caught, but propagated to the caller, as they may
	      indicate misconfigurations of the log  facility  or  errors  in  the  callers  code
	      itself.

       ::log::logMsg text
	      Convenience wrapper around ::log::log.  Equivalent to ::log::log info text.

       ::log::logError text
	      Convenience wrapper around ::log::log.  Equivalent to ::log::log error text.

       ::log::Puts level text
	      The  standard  log  command,  it writes messages and their levels to user-specified
	      channels. Assumes that the suppression checks were done by the caller. Expects full
	      level names, abbreviations are not allowed.

LEVELS
       The  package  currently	defines the following log levels, the level of highest importance
       listed first.

       o      emergency

       o      alert

       o      critical

       o      error

       o      warning

       o      notice

       o      info

       o      debug

KEYWORDS
       log, log level, message level, message

log					      1.0.1					   log(n)


All times are GMT -4. The time now is 09:37 AM.

Unix & Linux Forums Content Copyrightę1993-2018. All Rights Reserved.
UNIX.COM Login
Username:
Password:  
Show Password