Getting Started with QNX Neutrino - QNX Software Systems

time1.c
© 2009, QNX Software Systems GmbH & Co. KG.
int chid; // channel ID (global)
int debug = 1; // set debug value, 1 == enabled, 0 == off
char *progname = "time1.c";
// forward prototypes
static void setupPulseAndTimer (void);
static void gotAPulse (void);
static void gotAMessage (int rcvid, ClientMessageT *msg);
int
main (void)
{
int rcvid;
MessageT msg;
// ignore command-line arguments
// process ID of the sender
// the message itself
if ((chid = ChannelCreate (0)) == -1) {
fprintf (stderr, "%s: couldn’t create channel!\n", progname);
perror (NULL);
exit (EXIT_FAILURE);
}
// set up the pulse and timer
setupPulseAndTimer ();
// receive messages
for (;;) {
rcvid = MsgReceive (chid, &msg, sizeof (msg), NULL);
}
// determine who the message came from
if (rcvid == 0) {
// production code should check "code" field...
gotAPulse ();
} else {
gotAMessage (rcvid, &msg.msg);
}
}
// you’ll never get here
return (EXIT_SUCCESS);
/*
* setupPulseAndTimer
*
* This routine is responsible for setting up a pulse so it
* sends a message with code MT_TIMER. It then sets up a periodic
* timer that fires once per second.
*/
void
setupPulseAndTimer (void)
{
timer_t timerid; // timer ID for timer
struct sigevent event; // event to deliver
struct itimerspec timer; // the timer data structure
int coid; // connection back to ourselves
// create a connection back to ourselves
coid = ConnectAttach (0, 0, chid, 0, 0);
if (coid == -1) {
fprintf (stderr, "%s: couldn’t ConnectAttach to self!\n", progname);
perror (NULL);
exit (EXIT_FAILURE);
318 Appendix: C • Sample Programs April 30, 2009