Index: include/asterisk/time.h
===================================================================
--- include/asterisk/time.h	(revision 89277)
+++ include/asterisk/time.h	(working copy)
@@ -1,4 +1,4 @@
-/*
+*
  * Asterisk -- An open source telephony toolkit.
  *
  * Copyright (C) 1999 - 2005, Digium, Inc.
@@ -36,6 +36,20 @@
 typedef typeof(tv.tv_usec) ast_suseconds_t;
 
 /*!
+ * \brief Computes the difference (in microseconds) between two \c struct \c timeval instances.
+ * \param end the beginning of the time period
+ * \param start the end of the time period
+ * \return the difference in microseconds
+ */
+AST_INLINE_API(
+int64_t ast_tvdiff_us(struct timeval end, struct timeval start),
+{
+	return (end.tv_sec - start.tv_sec) * 1000000L +
+		end.tv_usec - start.tv_usec;
+}
+)
+
+/*!
  * \brief Computes the difference (in milliseconds) between two \c struct \c timeval instances.
  * \param end the beginning of the time period
  * \param start the end of the time period