Does nothing if err is null; if err is non-null, then *err
must be null. A new GLib.Error is created and assigned to *err.
Unlike g_set_error(), message is not a printf()-style format string.
Use this function if message contains text you don't have control over,
that could include printf() escape sequences.
Does nothing if
errisnull; iferris non-null, then*errmust benull. A new GLib.Error is created and assigned to*err. Unlikeg_set_error(),messageis not aprintf()-style format string. Use this function ifmessagecontains text you don't have control over, that could includeprintf()escape sequences.