+ * para_play distributes its work by submitting various tasks to the paraslash
+ * scheduler. The receiver, filter and writer tasks, which are used to play an
+ * audio file, require one task each to maintain their underlying buffer tree
+ * node. These tasks only exist when an audio file is playing.
+ *
+ * The i9 task, which is submitted and maintained by the i9e subsystem, reads
+ * an input line and calls the corresponding command handler such as com_stop()
+ * which is implemented in this file. The command handlers typically write a
+ * request to the global play_task structure, whose contents are read and acted
+ * upon by another task, the play task.
+ *
+ * As a rule, playlist handling is performed exclusively in play context, i.e.
+ * in the post-monitor step of the play task, while command handlers are only
+ * called in i9e context.
+ *
+ * \return EXIT_FAILURE or EXIT_SUCCESS.