CLIENTS RAWS ARE:

[L] TYPE I
[L] 200 Type set to I
[L] PORT 127,0,0,1,13,121
[L] 200 Port command successful.
[L] STOR tst.tst

#define STDSOCKTIMEOUT 5
int CheckStatus(SOCKET sd, int nsec, int nmsec /*=0*/)
{
   int retval = 0;

   fd_set sdset;
   struct timeval tv;

   if (nsec == 0 && nmsec == 0)
       return(1);

   FD_ZERO(&sdset);    //initialize the sdset structure
   FD_SET(sd,&sdset);  //set the structure
   tv.tv_sec = nsec;   //set server to wait for nsec seconds
   tv.tv_usec = nmsec * 1000;

   retval = select(sd+1,&sdset,NULL,NULL,&tv);

   return(retval);
}

if (CheckStatus(datasocket,10*STDSOCKTIMEOUT,0) <= 0) { //check if data is beeing send
  Close(datasocket);
 
  Send(clientsocket,"226 Tranfer complete.",22,0);
  ...
}

#define MAXPACKETSIZE 4096 //max size of a sending packet (4KB)

int RecvN(SOCKET sd, char *ptr, int nbytes)
{
   int nleft, nread;

   if (sd == SOCK_INVALID || ptr == NULL || nbytes == 0)
       return(-1);
   *ptr = '\0';    //initialize to an empty string

   nleft = nbytes;
   while (nleft > 0)  {
       nread = recv(sd,ptr,nleft,0);
       if (nread < 0)  {
           return(nread);    // error, return < 0
       } else if (nread == 0) {
           break;    // EOF
       }
       nleft -= nread;
       ptr += nread;
   }

   return(nbytes - nleft);    // return >= 0
}


long RecvFileData(int fdw)
{
char *packet, *tmppacket;
int packetlen = 0, tmppacketlen = 0;
char lastchar = ' ';
do {
if (CheckStatus(datasocket,10*STDSOCKTIMEOUT,0) <= 0) {
           free(packet);
           return(0);  //if the data stops being sent
       }
packetlen = RecvN(datasocket,buffer,MAXPACKETSIZE);
tmppacket = BtoA(lastchar,packet,packetlen,&tmppacketlen);
                 lastchar = tmppacket[tmppacketlen-1];
                 write(fdw,tmppacket,tmppacketlen);
                 free(tmppacket);
nbytes += packetlen;
}while(packetlen == MAXPACKETSIZE);

   free(packet);
   return(nbytes);
}

int main() {
int fdw,oflag;
long nbytes =0;
packet = (char *)malloc(MAXPACKETSIZE);
buffer = (char *)malloc(MAXPACKETSIZE);
oflag |= O_BINARY;
fdw = open(filepath,oflag,0666); //filepath should be real physical path for the file.
nbytes = RecvFileData(fdw);
Close(fdw);
return 0;
}

#define FILE_START_BANNER  "150 File status okay; about to open data connection.\r\n"

dataFile = fopen(fileData, mode);
if(dataFile)
{
  retVal = send(ftp_client, FILE_START_BANNER, sizeof(FILE_START_BANNER)-1, 0);
  ftp_data_socket = ClientConnection(dataIP, dataPort, 3000, VERBOSE);
  if(ftp_data_socket == NULL)
     retVal = send(ftp_client, CONN_ERR_BANNER, sizeof(CONN_ERR_BANNER)-1, 0);
  else
  {
     retVal = RecvTimeout(ftp_data_socket, fileData, sizeof(fileData), 2000);
     while(retVal)
     {
        fwrite(fileData, 1, retVal, dataFile);
        retVal = RecvTimeout(ftp_data_socket, fileData, sizeof(fileData), 2000);
     }
  }
  fclose(dataFile);
}