Specifies the prototype of log handler functions.

The default log handler, g_log_default_handler(), automatically appends a new-line character to message when printing it. It is advised that any custom log handler functions behave similarly, so that logging calls in user code do not need modifying to add a new-line character to the message if the log handler is changed.

This is not used if structured logging is enabled; see [Using Structured Logging][using-structured-logging].

alias GLogFunc = void function(const(char)* logDomain, GLogLevelFlags logLevel, const(char)* message, void* userData)