Writing to PVs

["Xu HuiJuan" <xuhuij@ihep.ac.cn>]

Hello,
I compiled the following code but there were several errors and I don't know
how to solve those problems.
Here is the code:

#include "stdafx.h"
#include <cadef.h>

#define MAXLEN 20
#define POLL 1.0e-9
#define SHRT_DLY 0.1
#define LNG_DLY 0.25

struct Channel
{
    dbr_string_t name;
    chid chan;
    struct Channel *next;
    struct Channel *prev;
}*pFirst=NULL,*pLast;

void connect_handler1(struct connection_handler_args);
void connect_handler2(struct connection_handler_args);
void an_event_handler(struct event_handler_args);
struct Channel *search(char *Name);

int main()
{
    int status,i,j,k;
    dbr_float_t *pValue;
    dbr_string_t Value;
    dbr_string_t Name[MAXLEN];
    struct Channel *pCurrent;
    unsigned long Nelem;

    /*initialize Channel Access task*/
    SEVCHK(ca_task_initialize(),"Unable to initialize");

    /*Get channel names and establish connection for each.*/
    /*Allocat memory for first node, and then for each additional node*/
    /*after connection is established. Loop until user enters "quit".*/

    for(printf("Enter a channel name.\n"),
         pCurrent=(struct Channel *)calloc(1,sizeof(struct
Channel));
          gets(Name)!=NULL&&strcmp(Name,"quit")!
=0;
         printf("Enter a channel name or \"quit\" to stop.\n"))
     {
          SEVCHK(status,NULL);
          ca_pend_event(LNG_DLY);
          if(ca_state(pCurrent->chan)!=cs_conn)
               printf("couldn't establish connection to %
s;ignoring\n",pCurrent->name);
          else
               pCurrent=(struct Channel *)calloc(1,sizeof(struct
Channel));
     }

    //Install a dirrerent connection handler on each channel.
     if(pFirst!=NULL)
     {
          for(pCurrent=pFirst;pCurrent!=NULL;pCurrent=pCurrent->next)
          {
               status=ca_change_connection_event(pCurrent-
>chan,connect_handler2);
               SEVCHK
(status,"ca_change_connection_event:couldn't change handler");
          }

     }
     ca_flush_io();

    //Loop until "quit" is entered. Get Channel name.
    //If found, prompt for values; else skip rest of loop.
    //Call ca_put_callback().
    for(i=0,printf("%s\n%s\n","Enter the PV's name","Enter \"quit\" to
stop");
          gets(pCurrent->name)!=NULL&&strcmp(pCurrent->name,"quit")!
=0;
          printf("%s\n","Enter PV name or \"quit\" to stop"))
     {
          ca_pend_event(POLL);
          pCurrent=search(Name);
          if(pCurrent==NULL)
          {
               printf("Cannot find channel name in list.
Disconnected?\n");
               continue;
          }
          Nelem=ca_element_count(pCurrent->chan);
          if(Nelem==1)
          {
               printf("Enter value.\n");
               if(gets(Value)!=NULL)
               {
                     status=ca_put_callback
(DBR_STRING,//EXTERNAL TYPE
                                         
     pCurrent->chan,//chid
                                         
    Value,//string of value
                                         
     an_event_handler,//callback
                                         
    pCurrent/*user supplied address*/);
                     SEVCHK(status,NULL);
               }
          }
         else if(Nelem>1)
          {
               printf("Enter up to %u values or q to
quit.\n",Nelem);
               pValue=(float *)calloc(Nelem,sizeof(*pValue));
               for(k=0;(j=scanf("%f",pValue+k))==1&&j!
=EOF&&k<Nelem;k++)
                     ;
               j=getchar();
               status=ca_array_put_callback(DBR_FLOAT,//external
type
                                         
         Nelem,//no. of elements to be sent
                                         
          pCurrent->chan,//chid
                                         
         pValue,//array of vlaues
                                         
          an_event_handler,//callback
                                         
         pCurrent/*user supplied address*/);
               SEVCHK(status,NULL);
          }
          ca_pend_event(SHRT_DLY);
     }
    return 0;
}

void connect_handler1(struct connection_handler_args connect_args)
{
    struct Channel *pCurrent;

    //set point to user-supplied address
     pCurrent->chan=ca_puser(connect_args.chid);

    //if connect up, initialize list or add node
     if(connect_args.op==CA_OP_CONN_UP)
     {
          if(pFirst==NULL)
          {
               pFirst=pCurrent;
               pFirst->prev=NULL;
               pLast=pCurrent;
          }
          pLast->next=pCurrent;
          pCurrent->prev=pLast;
          pCurrent->next=NULL;
          pLast=pCurrent;
         printf("%s is connected.\n",pCurrent->name);
     }
    //if connection down print message .
    //this block is unlikely to ever be used.

     else
         printf("%s is not connected.\n",pCurrent->name);
     return;
}

void connect_handler2(struct connection_handler_args connect_args)
{
    struct Channel *pCurrent;
    struct Channel *pPrevious,*pNext;

    //if connection down, free memory of user supplied address,
    //and delete nodes from list.
     if(connect_args.op==CA_OP_CONN_DOWN)
     {
          pCurrent=ca_puser(connect_args.chid);
          if(connect_args.op==CA_OP_CONN_DOWN)
          {
               pPrevious=pCurrent->prev;
               pNext=pCurrent->next;
               pPrevious->next=pNext;
               pNext->prev=pPrevious;
               free(pCurrent);
          }
         else if(pCurrent==pLast&&pCurrent!=pFirst)
          {
               pLast=pCurrent->prev;
               pLast->next=NULL;
               free(pCurrent);
          }
         else if(pCurrent==pFirst&&pCurrent!=pLast)
          {
               pFirst=pCurrent->next;
               pFirst->prev=NULL;
               free(pCurrent);
          }
         else if(pCurrent==pFirst&&pCurrent==pLast)
          {
               pFirst=NULL;
               pLast=NULL;
               free(pCurrent);
          }
         printf("%s:channel disconnected.\n",ca_name
(connect_args.chid));
     }
    //if re-connected, re-allocate memory
    else if(connect_args.op==CA_OP_CONN_UP)
     {
         pCurrent=(struct Channel *)calloc(1,sizeof(struct
Channel));
          connect_args.chid->puser=pCurrent;
          strcpy(pCurrent->name,ca_name(connect_args.chid));
          if(pFirst==NULL)
          {
               pFirst=pCurrent;
               pFirst->prev=NULL;
               pLast=pCurrent;
               pCurrent->next=NULL;
          }
          else
          {
               pLast->next=pCurrent;
               pCurrent->prev=pLast;
               pCurrent->next=NULL;
               pLast=pCurrent;
          }
         printf("%s:channel re-connected.\n",pCurrent->name);
     }
     return;
}


void an_event_handler(struct event_handler_args handler_args)
{
     if(handler_args.status!=ECA_NORMAL)
     {
         printf("channel %s:put operation not successful.\n",ca_name
(handler_args.chid));
          SEVCHK(handler_args.status,NULL);
     }
     else
         printf("channel %s:put operation completed.\n");
     return;
}

connect_args.chid->puser=pCurrent;                using undefined type“oldChannelNotify”

pCurrent=ca_puser(connect_args.chid);           can't convert“void *”to“Channel *” 

pCurrent->chan=ca_puser(connect_args.chid); can't convert“void *” to“chid”
I wonder how to solve it.

Thanks!