/* mktwatch.c : *  * Get datagram stock market * quotes from central quotes * server : */#include "quotes.h"/* * -b option (broadcast) address : */static char *cmdopt_b = DFLT_BCAST;/* * Display command usage : */static voidusage(void) {    puts("Usage:\tmktwatch [-b bcast]");    puts("where:");    puts("\t-b bcast\tBroadcast address");}/* * Extract ticker information from * broadcast datagram packet: */static intextract(char *dgram,TickReq *tkr) {    char *cp = dgram;    memset(tkr,0,sizeof *tkr);    strncpy(tkr->ticker,dgram,TICKLEN)        [TICKLEN] = 0;    cp += strlen(cp) + 1;    if ( sscanf(cp,"%lE",&tkr->last_trade) != 1 )        return -1;    cp += strlen(cp) + 1;    tkr->date = cp;    cp += strlen(cp) + 1;    tkr->time = cp;    cp += strlen(cp) + 1;    if ( sscanf(cp,"%lE",&tkr->change) != 1 )        return -1;    cp += strlen(cp) + 1;    if ( sscanf(cp,"%lE",&tkr->open_price) != 1 )        return -1;    cp += strlen(cp) + 1;    if ( sscanf(cp,"%lE",&tkr->high) != 1 )        return -1;    cp += strlen(cp) + 1;    if ( sscanf(cp,"%lE",&tkr->low) != 1 )        return -1;    cp += strlen(cp) + 1;    if ( sscanf(cp,"%lE",&tkr->volume) != 1 )        return -1;    return 0;}/* * Market Watch Main Program : */intmain(int argc,char **argv) {    int rc = 0;     /* Command return code */    int optch;         /* Option character */    int z;                  /* Status code */    int s;                       /* Socket */    socklen_t bc_len;           /* length  */    struct sockaddr_in bc_addr; /* AF_INET */    socklen_t a_len;     /* Address length */    struct sockaddr_in adr;     /* AF_INET */    char dgram[2048];       /* Recv buffer */    const int True = TRUE;  /* True const. */    TickReq tkr;            /* Ticker Data */    const char cmdopts[] = "hb:";    /*     * Parse command line options :     */    while ( (optch = getopt(argc,argv,cmdopts)) != -1 )        switch ( optch ) {        case 'h' :            /* -h (help) */            usage();            return rc;        case 'b' :           /* -b bc_addr */            cmdopt_b = optarg;            break;        default :            /* Option error */            rc = 1;    }    if ( rc ) {        usage();          /* Option errors */        return rc;    }            /*     * Form broadcast address :     */    bc_len = sizeof bc_addr;    z = mkaddr(        &bc_addr,   /* Returned addr. */        &bc_len,    /* Returned len. */        cmdopt_b,   /* Input address */        "udp");     /* UDP protocol */    if ( z == -1 ) {        fprintf(stderr,            "%s: -b %s",            strerror(errno),            cmdopt_b);        return 1;    }    /*     * Create a UDP socket to read from :     */    s = socket(PF_INET,SOCK_DGRAM,0);    if ( s == -1 ) {        fprintf(stderr,            "%s: socket(2)\n",            strerror(errno));        return 1;    }    /*     * Allow multiple listeners on this     * broadcast address :     */    z = setsockopt(s,        SOL_SOCKET,        SO_REUSEADDR,        &True,        sizeof True);        if ( z == -1 ) {        fprintf(stderr,            "%s: setsockopt(SO_REUSEADDR)\n",            strerror(errno));        return 1;    }    /*     * Bind to the broadcast address :     */    z = bind(s,        (struct sockaddr *)&bc_addr,bc_len);    if ( z == -1 ) {        fprintf(stderr,            "%s: bind(%s)\n",            strerror(errno),            cmdopt_b);        return 1;    }    /*     * Now listen for and process broadcasted     * stock quotes :     */    for (;;) {        /*         * Wait for a broadcast message :         */        a_len = sizeof adr; /* Max addr len. */        z = recvfrom(s,            /* Socket */            dgram,       /* Receiving buffer */            sizeof dgram,/* Max rcv buf size */            0,          /* Flags: no options */            (struct sockaddr *)&adr, /* Addr */            &a_len);   /* Addr len, in & out */        if ( z < 0 ) {            fprintf(stderr,                "%s: recvfrom(2)\n",                strerror(errno));            break;        }        /*         * Extract and report quote :         */        if ( !extract(dgram,&tkr) ) {            printf("%-*s %7.3f %s %7s %+7.3f %7.3f "                "%7.3f %7.3f %9.0f\n",                TICKLEN,                tkr.ticker,                tkr.last_trade,                tkr.date,                tkr.time,                tkr.change,                tkr.open_price,                tkr.high,                tkr.low,                tkr.volume);            fflush(stdout);        }    }    return 0;}