X-Git-Url: http://git.tuebingen.mpg.de/?a=blobdiff_plain;f=sched.h;h=f89b89ffc012551e17febc9de463882eb5c678b6;hb=7e0a0badba66c0cdcb0dcbc8cf3d0f5b71001ca3;hp=d9e852447ec55c27e4fc77a86185fcaa4a68bd06;hpb=bb899fb1a0c279a2890ff30d11bf7aec50fb92ed;p=paraslash.git

diff --git a/sched.h b/sched.h
index d9e85244..f89b89ff 100644
--- a/sched.h
+++ b/sched.h
@@ -11,6 +11,8 @@
  * function which is called from the scheduler main loop before it calls
  * select(). Similarly, each task must define a post_select function which is
  * called after the select call.
+ *
+ * \sa select(2), poll(2).
  */
 struct sched {
 	/** Initial value (in milliseconds) before any pre_select call. */
@@ -36,18 +38,27 @@ struct task_info {
 	/** Used for log messages and by \ref get_task_list(). */
 	const char *name;
 	/**
-	 * The optional pre select method.
+	 * Configure watch fds and impose an upper bound on the I/O timeout.
+	 *
+	 * If this is not NULL, the function is called at each iteration of the
+	 * scheduler's main loop. Its purpose is to tell the scheduler that
+	 * certain file descriptors should be monitored for readiness for I/O.
+	 * The function may also lower the scheduler's timeout value (but shall
+	 * never increase it) to impose an upper bound on the waiting time in
+	 * case no file descriptors happen to be ready.
 	 *
-	 * Its purpose is to add file descriptors to the fd sets of the
-	 * scheduler and to decrease the select timeout if necessary.
+	 * \sa \ref time.c.
 	 */
 	void (*pre_select)(struct sched *s, void *context);
 	/**
-	 * The mandatory post select method.
+	 * Perform I/O on file descriptors which are ready for I/O.
+	 *
+	 * This mandatory hook is called after the system call which monitors
+	 * file descriptors returns. The function should perform non-blocking
+	 * I/O on those file descriptors which are reported as being ready.
 	 *
-	 * Its purpose is to evaluate and act upon the results of the previous
-	 * select call. If this function returns a negative value, the
-	 * scheduler unregisters the task.
+	 * If this function returns a negative value, the scheduler unregisters
+	 * the task.
 	 */
 	int (*post_select)(struct sched *s, void *context);
 	/**