merges r27930 from trunk into ruby_1_9_2.

--
* thread.c (subtract_tv): if the rest is zero, should finish waiting
  immediately.

* win32/win32.c (subtract): ditto.
  based on a patch from Roger Pack in [ruby-core:27957].

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_2@27975 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 4 insertions, 1 deletions

diff --git a/thread.c b/thread.c
index f6b3b67df4..1956721da7 100644
--- a/thread.c
+++ b/thread.c
@@ -2411,6 +2411,9 @@ cmp_tv(const struct timeval *a, const struct timeval *b)
 static int
 subtract_tv(struct timeval *rest, const struct timeval *wait)
 {
+    if (rest->tv_sec < wait->tv_sec) {
+	return 0;
+    }
     while (rest->tv_usec < wait->tv_usec) {
 	if (rest->tv_sec <= wait->tv_sec) {
 	    return 0;
@@ -2420,7 +2423,7 @@ subtract_tv(struct timeval *rest, const struct timeval *wait)
     }
     rest->tv_sec -= wait->tv_sec;
     rest->tv_usec -= wait->tv_usec;
-    return 1;
+    return rest->tv_sec != 0 || rest->tv_usec != 0;
 }
 #endif