writer_default

Format a structured log message and output it to the default log destination for the platform.

On Linux, this is typically the systemd journal, falling back to `stdout` or `stderr` if running from the terminal or if output is being redirected to a file.

Support for other platform-specific logging mechanisms may be added in future. Distributors of GLib may modify this function to impose their own (documented) platform-specific log writing policies.

This is suitable for use as a [type@GLib.LogWriterFunc], and is the default writer used if no other is set using [func@GLib.log_set_writer_func ].

As with [func@GLib.log_default_handler], this function drops debug and informational messages unless their log domain (or `all`) is listed in the space-separated `G_MESSAGES_DEBUG` environment variable, or set at runtime by [func@GLib.log_writer_default_set_debug_domains].

[func@GLib.log_writer_default] uses the mask set by [func@GLib.log_set_always_fatal] to determine which messages are fatal. When using a custom writer function instead it is up to the writer function to determine which log messages are fatal.

Parameters:

fields	key–value pairs of structured data forming the log message
log_level	log level, either from [type@GLib.LogLevelFlags], or a user-defined level
n_fields	number of elements in the fields array
user_data	user data passed to [func@GLib.log_set_writer_func]

Returns:

[enum@GLib.LogWriterOutput.HANDLED] on success, [enum@GLib.LogWriterOutput.UNHANDLED] otherwise