* EXAMPLE* If the following code were executed by task 20:* .CS*     {*     name = "GRONK";*     num = 123;**     logMsg ("ERROR - name = %s, num = %d.\en", name, num, 0, 0, 0, 0);*     }* .CE* the following error message would appear on the system log:* .CS*     0x180400 (t20): ERROR - name = GRONK, num = 123.* .CE** RETURNS: The number of bytes written to the log queue,* or EOF if the routine is unable to write a message.** SEE ALSO: printf(), logTask()*/int logMsg    (    char *fmt,  /* format string for print */    int arg1,   /* first of six required args for fmt */    int arg2,    int arg3,    int arg4,    int arg5,    int arg6    )    {    int timeout;    LOG_MSG msg;    if (INT_CONTEXT ())	{	msg.id = -1;	timeout = NO_WAIT;	}    else	{	msg.id = taskIdSelf ();	timeout = WAIT_FOREVER;	}    msg.fmt    = fmt;    msg.arg[0] = arg1;    msg.arg[1] = arg2;    msg.arg[2] = arg3;    msg.arg[3] = arg4;    msg.arg[4] = arg5;    msg.arg[5] = arg6;    if (msgQSend (logMsgQId, (char *) &msg, sizeof (msg), timeout,		  MSG_PRI_NORMAL) != OK)	{	++logMsgsLost;	return (EOF);	}    return (sizeof (msg));    }/********************************************************************************* logFdSet - set the primary logging file descriptor** This routine changes the file descriptor where messages from logMsg() * are written, allowing the log device to be changed from the default* specified by logInit().  It first removes the old file descriptor (if * one had been previously set) from the log file descriptor list, then * adds the new <fd>.** The old logging file descriptor is not closed or affected by this call; * it is simply no longer used by the logging facilities.** RETURNS: N/A** SEE ALSO: logFdAdd(), logFdDelete()*/void logFdSet    (    int fd      /* file descriptor to use as logging device */    )    {    static int oldLogFd = NONE;    if (oldLogFd != NONE)	logFdDelete (oldLogFd);    /* if we are called from an rlogin session, remove pty fd from log fd list */    if (logFdFromRlogin != NONE)	{	logFdDelete (logFdFromRlogin);	logFdFromRlogin = NONE;		/* reset since its deleted from list */	}    if (logFdAdd (fd) == OK)	oldLogFd = fd;    else	oldLogFd = NONE;    }/********************************************************************************* logFdAdd - add a logging file descriptor** This routine adds to the log file descriptor list another file descriptor* <fd> to which messages will be logged.  The file descriptor must be a * valid open file descriptor.** RETURNS:* OK, or ERROR if the allowable number of additional logging file descriptors* (5) is exceeded.** SEE ALSO: logFdDelete()*/STATUS logFdAdd    (    int fd      /* file descriptor for additional logging device */    )    {    semTake (&logFdSem, WAIT_FOREVER);    if ((numLogFds + 1) > MAX_LOGFDS)	{	semGive (&logFdSem);	/* XXX errnoSet (S_logLib_TOO_MANY_LOGGING_FDS); */	return (ERROR);	}    logFd [numLogFds++] = fd;    semGive (&logFdSem);    return (OK);    }/********************************************************************************* logFdDelete - delete a logging file descriptor** This routine removes from the log file descriptor list a logging file * descriptor added by logFdAdd().  The file descriptor is not closed; but is* no longer used by the logging facilities.** RETURNS:* OK, or ERROR if the file descriptor was not added with logFdAdd().** SEE ALSO: logFdAdd()*/STATUS logFdDelete    (    int fd      /* file descriptor to stop using as logging device */    )    {    FAST int ix;    FAST int jx;    semTake (&logFdSem, WAIT_FOREVER);    for (ix = jx = 0; ix < numLogFds; ix++, jx++)	{	/* shift array of logFd's after deleting unwanted fd */	if (((logFd [jx] = logFd [ix]) == fd) && ix == jx)	    jx--;	}    if (ix == jx)	{	semGive (&logFdSem);	return (ERROR);		/* didn't find specified fd */	}    numLogFds--;    semGive (&logFdSem);    return (OK);    }/********************************************************************************* logTask - message-logging support task** This routine prints the messages logged with logMsg().  It waits on a* message queue and prints the messages as they arrive on the file descriptor* specified by logInit() (or a subsequent call to logFdSet() or logFdAdd()).** This task is spawned by logInit().** RETURNS: N/A** SEE ALSO: logMsg()*/void logTask (void)    {    static int oldMsgsLost;    int newMsgsLost;	/* used in case logMsgsLost is changed during use */    LOG_MSG msg;    char *checkName;    FOREVER	{	if (msgQReceive (logMsgQId, (char *) &msg, sizeof (msg),			 WAIT_FOREVER) != sizeof (msg))	    lprintf ("logTask: error reading log messages.\n", 0, 0, 0, 0, 0,0);	else	    {	    /* print task ID followed by caller's message */	    /* print task ID */	    if (msg.id == -1)		{		lprintf ("interrupt: ", 0, 0, 0, 0, 0, 0);		}	    else		{		if ((checkName = taskName (msg.id)) == NULL)		    lprintf ("%#x (): task dead", msg.id, 0, 0, 0, 0, 0);		else		    lprintf ("%#x (%s): ", msg.id, (int)checkName, 0, 0, 0, 0);		}	    if (msg.fmt == NULL)		lprintf ("<null \"fmt\" parameter>\n", 0, 0, 0, 0, 0, 0);	    else		{		lprintf (msg.fmt, msg.arg[0], msg.arg[1], msg.arg[2],				  msg.arg[3], msg.arg[4], msg.arg[5]);		}	    }	/* check for any more messages lost */	newMsgsLost = logMsgsLost;	if (newMsgsLost != oldMsgsLost)	    {	    lprintf ("logTask: %d log messages lost.\n",		     newMsgsLost - oldMsgsLost, 0, 0, 0, 0, 0);	    oldMsgsLost = newMsgsLost;	    }	}    }/********************************************************************************* lprintf - log printf** Performs an fdprintf on all logFds.*/LOCAL void lprintf    (    char *fmt,	/* format string for print */    int arg1,	/* optional arguments to fmt */    int arg2,    int arg3,    int arg4,    int arg5,    int arg6     )    {    FAST int ix;    semTake (&logFdSem, WAIT_FOREVER);    for (ix = 0; ix < numLogFds; ix++)	fdprintf (logFd [ix], fmt, arg1, arg2, arg3, arg4, arg5, arg6);    semGive (&logFdSem);    }/********************************************************************************* logShow - show active logging fd's (debug only)** NOMANUAL*/void logShow (void)    {    FAST int ix;    printf ("%3s %3s\n", "num", "fd");    printf ("%3s %3s\n", "---", "--");    for (ix = 0; ix < numLogFds; ix++)	printf ("%3d %3d\n", ix, logFd [ix]);    /* XXX timeout, message size, ...    msgQShow (logMsgQId, 1);    */    }