X-Git-Url: http://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Flbalance%2Flbalance.h;h=943e1636603ea037e1de05bfb091785ed8c61396;hp=d318a6fe84b78344dd993f2b83a82e19df248d1d;hb=d9cbd7d4454ae35e4e2f6d18a9469bf26948e4b9;hpb=f69389e6806e2f0b63084576ffa4c84bba699147

diff --git a/ccan/lbalance/lbalance.h b/ccan/lbalance/lbalance.h
index d318a6fe..943e1636 100644
--- a/ccan/lbalance/lbalance.h
+++ b/ccan/lbalance/lbalance.h
@@ -1,3 +1,4 @@
+/* Licensed under GPLv3+ - see LICENSE file for details */
 #ifndef CCAN_LBALANCE_H
 #define CCAN_LBALANCE_H
 #include "config.h"
@@ -9,12 +10,41 @@ struct rusage;
 
 /**
  * lbalance_new - initialize a load balancing structure.
+ *
+ * Example:
+ *	struct lbalance *lb = lbalance_new();
+ *
+ *	// ...
+ *
+ *	lbalance_free(lb);
+ *	return 0;
  */
 struct lbalance *lbalance_new(void);
 
+/**
+ * lbalance_free - free a load balancing structure.
+ * @lbalance: the load balancer from lbalance_new.
+ *
+ * Also frees any tasks still attached.
+ */
+void lbalance_free(struct lbalance *lbalance);
+
 /**
  * lbalance_task_new - mark the starting of a new task.
  * @lbalance: the load balancer from lbalance_new.
+ *
+ * Example:
+ *	static pid_t run_child(struct lbalance *lb, struct lbalance_task **task)
+ *	{
+ *		pid_t pid = fork();
+ *		if (pid != 0) {
+ *			// We are the parent, return.
+ *			*task = lbalance_task_new(lb);
+ *			return pid;
+ *		}
+ *		// otherwise do some work...
+ *		exit(0);
+ *	}
  */
 struct lbalance_task *lbalance_task_new(struct lbalance *lbalance);
 
@@ -29,6 +59,21 @@ struct lbalance_task *lbalance_task_new(struct lbalance *lbalance);
  *
  * Otherwise, lbalance_task_free() is a noop, which is useful for failure
  * paths.
+ *
+ * Example:
+ *	#include <sys/types.h>
+ *	#include <sys/time.h>
+ *	#include <sys/resource.h>
+ *	#include <sys/wait.h>
+ *
+ *	static void wait_for_child(struct lbalance_task *task)
+ *	{
+ *		struct rusage ru;
+ *		// Wait for child to finish, get usage.
+ *		wait4(-1, NULL, 0, &ru);
+ *		// Tell lbalancer about usage, free struct lbalance_task.
+ *		lbalance_task_free(task, &ru);
+ *	}
  */
 void lbalance_task_free(struct lbalance_task *task,
 			const struct rusage *usage);
@@ -39,14 +84,23 @@ void lbalance_task_free(struct lbalance_task *task,
  *
  * Normally you keep creating tasks until this limit is reached.  It's
  * updated by stats from lbalance_task_free.
+ *
+ * Example:
+ *	int main(void)
+ *	{
+ *		unsigned int num_running = 0;
+ *		struct lbalance *lb = lbalance_new();
+ *
+ *		for (;;) {
+ *			// Run more until we reach target.
+ *			while (num_running < lbalance_target(lb)) {
+ *				// Run another one.
+ *			}
+ *
+ *			// Wait for something to finish.
+ *		}
+ *	}
  */
 unsigned lbalance_target(struct lbalance *lbalance);
 
-/**
- * lbalance_free - free a load balancing structure.
- * @lbalance: the load balancer from lbalance_new.
- *
- * Also frees any tasks still attached.
- */
-void lbalance_free(struct lbalance *lbalance);
 #endif /* CCAN_LBALANCE_H */