From: Ben Harris <bjh21@bjh21.me.uk>
Date: Sat, 3 Nov 2018 14:25:04 +0000 (+0000)
Subject: Start keeping track of what time we think the clock is displaying.
X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~bjharris/git?a=commitdiff_plain;h=8f0ee44833ee4b77ec1f1d32beaa1235a9cf933f;p=clunk.git

Start keeping track of what time we think the clock is displaying.
---

diff --git a/clunk.c b/clunk.c
index c9b77d5..f7e7271 100644
--- a/clunk.c
+++ b/clunk.c
@@ -3,7 +3,9 @@
 #include <stdio.h>
 #include <time.h>
 
-long const pulsewidth = 250000000; /* nanoseconds */
+static long const pulsewidth = 250000000; /* nanoseconds */
+
+static struct tm displayed;
 
 static void
 pulse()
@@ -13,8 +15,35 @@ pulse()
 	printf("ker...");
 	fflush(stdout);
 	clock_nanosleep(CLOCK_MONOTONIC, 0, &ts, NULL);
-	printf("chunk!\n");
+	printf("chunk!");
+	displayed.tm_sec += 30;
+	while (displayed.tm_sec >= 60) {
+		displayed.tm_min++;
+		displayed.tm_sec -= 60;
+	}
+	while (displayed.tm_min >= 60) {
+		displayed.tm_hour++;
+		displayed.tm_min -= 60;
+	}
+	displayed.tm_hour %= 12;
+	printf(" (%02d:%02d:%02d)\n",
+	       displayed.tm_hour, displayed.tm_min, displayed.tm_sec);
+	fflush(stdout);
+}
+
+static void
+init()
+{
+	struct timespec ts;
+
+	tzset();
+	if (clock_gettime(CLOCK_REALTIME, &ts) != 0)
+		err (1, "clock_gettime");
+	if (localtime_r(&ts.tv_sec, &displayed) == NULL)
+		err(1, "localtime_r");
+	displayed.tm_sec = (displayed.tm_sec >= 30) ? 30 : 0;
 }
+	
 
 static void
 run()
@@ -44,7 +73,7 @@ int
 main(int argc, char **argv)
 {
 
-	tzset();
+	init();
 	run();
 	return 0;
 }