QNX中name_attach 和nameopen的应用

文中示例来源于QNX IDE。

1、服务器端步骤：

1）name_attach():是在服务器端使用，在名称空间中定义一个name(客户端中对应open这个name),同时创建了一个channel.

name_attach_t * name_attach( dispatch_t * dpp,
                             const char * path,  //对应name
                             unsigned flags );

typedef struct _name_attach {
    dispatch_t* dpp;
    int         chid;  //对应 channel  id
    int         mntid;
    int         zero[2];
} name_attach_t;

 2） MsgReceive（）从chid中 接收消息：//返回值为0，表示收到pulse,返回值>0，表示收到message

3）name_detach()

2、客户端步骤：

1）name_open()打开服务器端 的name  ------>#define ATTACH_POINT "myname"

2）MsgSend（）；

3）name_close（）

 例：来源于QNX  IDE

#include 
#include 
#include 
#include 
#include 

#define ATTACH_POINT "myname"

/* We specify the header as being at least a pulse */
typedef struct _pulse msg_header_t;

/* Our real data comes after the header */
typedef struct _my_data {
    msg_header_t hdr;
    int data;
} my_data_t;

/*** Server Side of the code ***/
int server() {
   name_attach_t *attach;
   my_data_t msg;
   int rcvid;

   /* Create a local name (/dev/name/local/...) */
   if ((attach = name_attach(NULL, ATTACH_POINT, 0)) == NULL) {
       return EXIT_FAILURE;
   }

   /* Do your MsgReceive's here now with the chid */
   while (1) {
       rcvid = MsgReceive(attach->chid, &msg, sizeof(msg), NULL);

       if (rcvid == -1) {/* Error condition, exit */
           break;
       }

       if (rcvid == 0) {/* Pulse received */
           switch (msg.hdr.code) {
           case _PULSE_CODE_DISCONNECT:
               /*
                * A client disconnected all its connections (called
                * name_close() for each name_open() of our name) or
                * terminated
                */
               ConnectDetach(msg.hdr.scoid);
               break;
           case _PULSE_CODE_UNBLOCK:
               /*
                * REPLY blocked client wants to unblock (was hit by
                * a signal or timed out).  It's up to you if you
                * reply now or later.
                */
               break;
           default:
               /*
                * A pulse sent by one of your processes or a
                * _PULSE_CODE_COIDDEATH or _PULSE_CODE_THREADDEATH
                * from the kernel?
                */
               break;
           }
           continue;
       }

       /* name_open() sends a connect message, must EOK this */
       if (msg.hdr.type == _IO_CONNECT ) {
           MsgReply( rcvid, EOK, NULL, 0 );
           continue;
       }

       /* Some other QNX IO message was received; reject it */
       if (msg.hdr.type > _IO_BASE && msg.hdr.type <= _IO_MAX ) {
           MsgError( rcvid, ENOSYS );
           continue;
       }

       /* A message (presumable ours) received, handle */
       printf("Server receive %d \n", msg.data);
       MsgReply(rcvid, EOK, 0, 0);

   }

   /* Remove the name from the space */
   name_detach(attach, 0);

   return EXIT_SUCCESS;
}


/*** Client Side of the code ***/
int client() {
    my_data_t msg;
    int server_coid;

    if ((server_coid = name_open(ATTACH_POINT, 0)) == -1) {
        return EXIT_FAILURE;
    }

    /* We would have pre-defined data to stuff here */
    msg.hdr.type = 0x00;
    msg.hdr.subtype = 0x00;

    /* Do whatever work you wanted with server connection */
    for (msg.data=0; msg.data < 5; msg.data++) {
        printf("Client sending %d \n", msg.data);
        if (MsgSend(server_coid, &msg, sizeof(msg), NULL, 0) == -1) {
            break;
        }
    }

    /* Close the connection */
    name_close(server_coid);
    return EXIT_SUCCESS;
}

int main(int argc, char **argv) {
    int ret;

    if (argc < 2) {
        printf("Usage %s -s | -c \n", argv[0]);
        ret = EXIT_FAILURE;
    }
    else if (strcmp(argv[1], "-c") == 0) {
        printf("Running Client ... \n");
        ret = client();   /* see name_open() for this code */
    }
    else if (strcmp(argv[1], "-s") == 0) {
        printf("Running Server ... \n");
        ret = server();   /* see name_attach() for this code */
    }
    else {
        printf("Usage %s -s | -c \n", argv[0]);
        ret = EXIT_FAILURE;
    }
    return ret;
}

注意：服务器断接收的数据（即客户端发送的数据），自定义的数据类型中，前面需要添加自带的msg_header_t hdr;消息头。

typedef struct _my_data {
    msg_header_t hdr;
    int data;
} my_data_t;