VxWorks多任务通信--管道

pipeServer.c

/* includes */#include "vxWorks.h"#include "taskLib.h"#include "stdio.h"#include "ioLib.h"#include "pipeDrv.h"typedef struct    {    VOIDFUNCPTR routine;    int arg;    } MSG_REQUEST;                          /* message structure */#define TASK_PRI        254             /* tServers task's priority */#define TASK_STACK_SIZE         5000            /* tServer task's stack size */#define PIPE_NAME       "/pipe/server"  /* name of the pipe device */#define NUM_MSGS                10     /* max number of messages in the pipe */LOCAL int pipeFd;                     /* File descriptor for the pipe device */LOCAL void pipeServer ();             /* server task *//*********************************************************************** * serverStart -- Initializes a server task to execute functons *                at a low priority.  Uses pipes as the communication *                mechanism. * * RETURNS: OK or ERROR on failure. */STATUS serverStart ()    {    if (pipeDevCreate (PIPE_NAME, NUM_MSGS, sizeof (MSG_REQUEST)) == ERROR)        {        perror ("Error in creating pipe"); /* print error if pipe is already                                             * created, but do not return */        }    /* Open the pipe */    if ((pipeFd = open (PIPE_NAME, UPDATE, 0)) == ERROR)        {        perror  ("Error in opening pipe device");        return (ERROR);        }    /* Spawn the server task */    if (taskSpawn ("tServer", TASK_PRI, 0, TASK_STACK_SIZE,                    (FUNCPTR) pipeServer, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)                    == ERROR)        {        perror ("Error in spawning tServer task");    close (pipeFd);    return (ERROR);    }    return (OK);    }/************************************************************** * serverSend -- Sends a request to the server to execute a  *               function at the server's  priority. * * RETURNS: OK or ERROR on failure. */STATUS serverSend     (    VOIDFUNCPTR routine,              /* name of the routine to execute */    int arg                           /* argument of the routine */            )    {    MSG_REQUEST msgRequest;    int status;    /* Initialize the message structure */    msgRequest.routine = routine;    msgRequest.arg     = arg;    /* Send the message and return the results */    status = write (pipeFd, (char *)&msgRequest, sizeof (MSG_REQUEST));    return ((status == sizeof (MSG_REQUEST)) ? OK : ERROR);    }/************************************************************************* * pipeServer -- Server task which reads from a pipe and executes *               the function passed in the MSG_REQUEST data structure. * */LOCAL void pipeServer ()    {    MSG_REQUEST msgRequest;    while (read (pipeFd, (char *)&msgRequest, sizeof (MSG_REQUEST)) > 0)        (*msgRequest.routine) (msgRequest.arg);        }