logDefaultHandler

fun logDefaultHandler(logDomain: String? = null, logLevel: LogLevelFlags, message: String? = null, unusedData: <Error class: unknown class>? = null)

The default log handler set up by GLib; func@GLib.log_set_default_handler allows to install an alternate default log handler.

This is used if no log handler has been set for the particular log domain and log level combination. It outputs the message to stderr or stdout and if the log level is fatal it calls func@GLib.BREAKPOINT. It automatically prints a new-line character after the message, so one does not need to be manually included in @message.

The behavior of this log handler can be influenced by a number of environment variables:

  • G_MESSAGES_PREFIXED: A :-separated list of log levels for which messages should be prefixed by the program name and PID of the application.

  • G_MESSAGES_DEBUG: A space-separated list of log domains for which debug and informational messages are printed. By default these messages are not printed. If you need to set the allowed domains at runtime, use func@GLib.log_writer_default_set_debug_domains.

stderr is used for levels flags@GLib.LogLevelFlags.LEVEL_ERROR, flags@GLib.LogLevelFlags.LEVEL_CRITICAL, flags@GLib.LogLevelFlags.LEVEL_WARNING and flags@GLib.LogLevelFlags.LEVEL_MESSAGE. stdout is used for the rest, unless stderr was requested by func@GLib.log_writer_default_set_use_stderr.

This has no effect if structured logging is enabled; see logging.html#using-structured-logging.

Parameters

logDomain

the log domain of the message, or NULL for the default "" application domain

logLevel

the level of the message

message

the message

unusedData

data passed from func@GLib.log which is unused