Sets the message levels which are always fatal, in any log domain.
When a message with any of these levels is logged the program terminates.
You can only set the levels defined by GLib to be fatal.
G_LOG_LEVEL_ERROR is always fatal.
You can also make some message levels fatal at runtime by setting
G_DEBUG environment variable (see
Running GLib Applications).
Libraries should not call this function, as it affects all messages logged by a process, including those from other libraries.
Structured log messages (using
g_log_structured_array()) are fatal only if the default log writer is used;
otherwise it is up to the writer function to determine which log messages
are fatal. See [Using Structured Logging][using-structured-logging].
The mask containing bits set for each level of error which is to be fatal.
The old fatal mask.