examples: add fork + signals + timer example

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

examples/Makefile.am

@@ -1,3 +1,3 @@
-noinst_PROGRAMS = ctrl joystick redirect
+noinst_PROGRAMS = ctrl forky joystick redirect
 AM_CPPFLAGS     = -I$(top_srcdir)/src
 LDADD           = $(top_srcdir)/src/libuev.la

examples/forky.c

@@ -0,0 +1,89 @@
+/* Example of how to handle signal, in this case Ctrl-C
+ * 
+ * A common problem for users of libuEV is how to combine it with the
+ * traditional aspects of UNIX.  Since libuEV is just a wrapper for
+ * signalfd() and epoll(), in this case, it can be worth a dedicated
+ * example.  After all, command line use with Ctrl-C is one of the most
+ * common use-cases.
+ */
+
+#include <stdio.h>
+#include <signal.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "src/uev.h"
+
+
+void timeout(uev_t *w, void *arg, int events)
+{
+	char *id = (char *)arg;
+
+	if (UEV_ERROR == events)
+		puts("Ignoring timer watcher error ...");
+
+	printf("I am the %s robot\n", id);
+}
+
+void teaser(uev_t *w, void *arg, int events)
+{
+	(void)arg;
+
+	if (UEV_ERROR == events)
+		puts("Ignoring SIGINT watcher error ...");
+
+	puts("\nWe are here to protect you ...");
+	puts("Sorry, you actually need to press Ctrl-\\ to exit.");
+}
+
+void cleanup(uev_t *w, void *arg, int events)
+{
+	(void)arg;
+
+	if (UEV_ERROR == events)
+		puts("Ignoring signal watcher error ...");
+
+	/* Graceful exit, with optional cleanup ... */
+	puts("\nAgainst the terrible secret of space.");
+
+	uev_exit(w->ctx);
+}
+
+int main(int argc, char **argv)
+{
+	uev_ctx_t ctx;
+	uev_t timerw;
+	uev_t sig1w;
+	uev_t sig2w;
+	char *robot;
+	pid_t pid;
+
+	pid = fork();
+	if (pid == -1)
+		return 1;
+	if (pid > 0)
+		robot = "Shover";
+	else
+		robot = "Pusher";
+
+	setsid();
+	uev_init(&ctx);
+
+	/* example worker, a timer callback */
+	uev_timer_init(&ctx, &timerw, timeout, robot, 100, 2000);
+
+	/* the owls are not what they seem ... */
+	uev_signal_init(&ctx, &sig1w, teaser,  NULL, SIGINT);
+	uev_signal_init(&ctx, &sig2w, cleanup, NULL, SIGQUIT);
+
+	puts("Starting, press Ctrl-C to exit.");
+
+	return uev_run(&ctx, 0);
+}
+
+/**
+ * Local Variables:
+ *  compile-command: "make forky; ./forky"
+ *  c-file-style: "linux"
+ * End:
+ */