time: time_mono() helpers.

[ccan] / ccan / time / time.h

diff --git a/ccan/time/time.h b/ccan/time/time.h
index 7bb3547d6227630fb5eb682544dc7e2eb4c2e6aa..46568425c7cd44594e3964d3f8435f316d11eed4 100644 (file)
--- a/ccan/time/time.h
+++ b/ccan/time/time.h
@@ -48,6 +48,28 @@ struct timeabs {
        struct timespec ts;
 };
 
+/**
+ * struct timemono - a monotonic time.
+ * @ts: the actual timespec value.
+ *
+ * This comes from the monotonic clock (if available), so it's useful
+ * for measuring intervals as it won't change even if the system clock
+ * is moved for some reason.
+ */
+struct timemono {
+       struct timespec ts;
+};
+
+/**
+ * TIME_HAVE_MONOTONIC - defined if we really have a monotonic clock.
+ *
+ * Otherwise time_mono() just refers to time_now().  Your code might
+ * test this if you really need a monotonic clock.
+ */
+#if (HAVE_CLOCK_GETTIME || HAVE_CLOCK_GETTIME_IN_LIBRT) && defined(CLOCK_MONOTONIC)
+#define TIME_HAVE_MONOTONIC 1
+#endif
+
 struct timespec time_check_(struct timespec in, const char *abortstr);
 
 /**
@@ -99,6 +121,16 @@ struct timeabs timeabs_check(struct timeabs in, const char *abortstr);
  */
 struct timeabs time_now(void);
 
+/**
+ * time_mono - return the current monotonic time
+ *
+ * This value is only really useful for measuring time intervals.
+ *
+ * See also:
+ *     time_since()
+ */
+struct timemono time_mono(void);
+
 static inline bool time_greater_(struct timespec a, struct timespec b)
 {
        if (TIME_CHECK(a).tv_sec > TIME_CHECK(b).tv_sec)
@@ -272,6 +304,22 @@ static inline struct timerel time_between(struct timeabs recent, struct timeabs
        return t;
 }
 
+/**
+ * timemono_between - time between two monotonic times
+ * @recent: the larger time.
+ * @old: the smaller time.
+ *
+ * This returns a well formed struct timerel of @recent - @old.
+ */
+static inline struct timerel timemono_between(struct timemono recent,
+                                             struct timemono old)
+{
+       struct timerel t;
+
+       t.ts = time_sub_(recent.ts, old.ts);
+       return t;
+}
+
 /**
  * timeabs_sub - subtract a relative time from an absolute time
  * @abs: the absolute time.