</para>
<para>
Of course, Glk can be used with other IF systems. The advantage of Glulx is that it provides the game author with direct and complete access to the Glk API. Other IF systems typically have an built-in abstract I/O API, which maps only partially onto Glk. For these systems, Glk tends to be a least-common-denominator interface: highly portable, but not necessarily featureful. (Even if Glk has a feature, it may not be available through the layers of abstraction.)
</para>
<para>
Of course, Glk can be used with other IF systems. The advantage of Glulx is that it provides the game author with direct and complete access to the Glk API. Other IF systems typically have an built-in abstract I/O API, which maps only partially onto Glk. For these systems, Glk tends to be a least-common-denominator interface: highly portable, but not necessarily featureful. (Even if Glk has a feature, it may not be available through the layers of abstraction.)