From: Ben Harris <bjh21@bjh21.me.uk>
Date: Sat, 24 Nov 2018 01:57:33 +0000 (+0000)
Subject: Simplify code to clear pending SIGALRM.
X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~bjharris/git?a=commitdiff_plain;h=d826d1933adeca7b707e28b9f4025147c9d04af8;p=clunk.git

Simplify code to clear pending SIGALRM.

A simple sigtimedwait() with a timeout of zero will do.  No need to
muck about with sigpending().
---

diff --git a/clunk.c b/clunk.c
index a924bba..4cb8a70 100644
--- a/clunk.c
+++ b/clunk.c
@@ -277,8 +277,6 @@ run()
 	struct timespec const timeout = { .tv_sec = 31, .tv_nsec = 0 };
 	struct tm tm;
 	int tick;
-	sigset_t pending_signals;
-	int signo;
 
 	while (true) {
 		if (clock_gettime(CLOCK_REALTIME, &ts) != 0)
@@ -315,14 +313,10 @@ run()
 			if (timer_settime(main_timer, 0,
 					  &its_disarm, NULL) != 0)
 				err(1, "timer_settime (disarm)");
-			/* Clear any pending SIGALRM. */
-			if (sigpending(&pending_signals) == -1)
-				err(1, "sigpending");
-			if (sigismember(&pending_signals, SIGALRM)) {
-				errno = sigwait(&timing_signals, &signo);
-				if (errno != 0)
-					err(1, "sigwait");
-			}
+			/* Clear any SIGALRM generated before timer disarmed */
+			if (sigtimedwait(&timing_signals, NULL, &TS_SEC(0))
+			    == -1 && errno != EAGAIN)
+				err(1, "sigtimedwait");
 		}
 	}
 }