Declarations

The first section of code here sets up the various manifest constants that we'll be using, the data structures, and includes all the header files required. We'll present this without comment. :-)

/*
 *  time1.c
 *
 *  Example of a server that receives periodic messages from
 *  a timer, and regular messages from a client.
 *
 *  Illustrates using the timer functions with a pulse.
*/

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <signal.h>
#include <errno.h>
#include <unistd.h>
#include <sys/siginfo.h>
#include <sys/neutrino.h>

// message send definitions

// messages
#define MT_WAIT_DATA        2       // message from client
#define MT_SEND_DATA        3       // message from client

// pulses
#define CODE_TIMER          1       // pulse from timer

// message reply definitions
#define MT_OK               0       // message to client
#define MT_TIMEDOUT         1       // message to client

// message structure
typedef struct
{
    // contains both message to and from client
    int messageType;
    // optional data, depending upon message
    int messageData;
} ClientMessageT;

typedef union
{
    // a message can be either from a client, or a pulse
    ClientMessageT  msg;
    struct _pulse   pulse;
} MessageT;

// client table
#define MAX_CLIENT 16       // max # of simultaneous clients

struct
{
    int in_use;             // is this client entry in use?
    int rcvid;              // receive ID of client
    int timeout;            // timeout left for client
}   clients [MAX_CLIENT];   // client table

int     chid;               // channel ID (global)
int     debug = 1;          // set debug value, 1=on, 0=off
char    *progname = "time1.c";

// forward prototypes
static  void setupPulseAndTimer (void);
static  void gotAPulse (void);
static  void gotAMessage (int rcvid, ClientMessageT *msg);