* process.c: [DOC] MACH_ABSOLUTE_TIME_CLOCK_MONOTONIC is an

  available emulation for a monotonic clock on Darwin.
  https://developer.apple.com/library/mac/qa/qa1398/_index.html

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42594 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 8 insertions, 2 deletions

diff --git a/process.c b/process.c
index 551bfd5d84..2ee9f4a04e 100644
--- a/process.c
+++ b/process.c
@@ -6671,14 +6671,20 @@ rb_proc_times(VALUE obj)
  *  [CLOCK_UPTIME_PRECISE] FreeBSD 8.1
  *  [CLOCK_SECOND] FreeBSD 8.1
  *
- *  Also, several symbols are accepted as +clock_id+.
- *  They may be used as emulation for clock_gettime().
+ *  Also, several other symbols are accepted as +clock_id+.
+ *  There are emulations for clock_gettime().
+ *
  *  For example, Process::CLOCK_REALTIME is defined as
  *  +:POSIX_GETTIMEOFDAY_CLOCK_REALTIME+ when clock_gettime() is not available.
  *
+ *  Emulations for +:CLOCK_REALTIME+:
  *  [:POSIX_GETTIMEOFDAY_CLOCK_REALTIME] Use gettimeofday().  The precision is 1 micro second.
  *  [:POSIX_TIME_CLOCK_REALTIME] Use time().  The precision is 1 second.
  *
+ *  Emulations for +:CLOCK_MONOTONIC+:
+ *  [:MACH_ABSOLUTE_TIME_CLOCK_MONOTONIC] Use mach_absolute_time(), available on Darwin.
+ * 					  The precision is CPU dependent.
+ *
  *  If the given +clock_id+ is not supported, Errno::EINVAL is raised.
  *
  *  +unit+ specifies a type of the return value.