VISA serial port reading/ writing

hi, i'm writing program for microcontroller that using serial port for reading and writing data.

after boot, program must to wait 10 seconds to receive data from serial port

code: init serial port by VISA

//init of ssp protocol
        viSetAttribute (ssp, VI_ATTR_TERMCHAR_EN, VI_FALSE);   //disable termination char
	viSetAttribute (ssp, VI_ATTR_ASRL_END_IN, VI_ASRL_END_LAST_BIT);
	viSetAttribute (ssp, VI_ATTR_ASRL_BAUD, 38400); 
	viSetAttribute (ssp, VI_ATTR_ASRL_PARITY, VI_ASRL_PAR_NONE);  
	viSetAttribute (ssp, VI_ATTR_TMO_VALUE, 15000); //TMO 15 seconds
	viFlush (ssp, VI_ASRL_IN_BUF_DISCARD);
	Sleep(1); 

reading from the port

if (!strcmp(command,"readBuffer")) //Reading TST 
{
          incount = 0;
          otcount = 0;
    viGetAttribute(ssp, VI_ATTR_ASRL_AVAIL_NUM, &num_bytes);
    while(num_bytes <= 3) 
    {
          viGetAttribute(ssp, VI_ATTR_ASRL_AVAIL_NUM, &num_bytes); 
          viRead (ssp, Databuf, num_bytes, &RTCount);
    } 

         Databuf[RTCount] = '\0';

         viFlush (ssp, VI_WRITE_BUF);
         viFlush (ssp, VI_READ_BUF);
         packetdata = strtok(Databuf,";");

         if(!strcmp(Databuf, ";TST;") || !strcmp(Databuf, ";TST") || !strcmp(Databuf, "TST;") || !strcmp(Databuf, "TST"))
         {

             InsertTextBoxLine (panelHandle, PANEL_DEBUGWINDOW , ++debugBoxLine, Databuf); 
              //*************** Auto Scroll ***********************
             SetCtrlAttribute (panelHandle, PANEL_DEBUGWINDOW, ATTR_FIRST_VISIBLE_LINE, debugBoxLine);
             flagout = 1; nboards++;
             return 1;
         }

 are this code optimal , can i change and remove while loop from the code?

and another issue when i'm writing to the port

code:

if(!strcmp(command,";ANALOG;")) 
	{
	     Sleep(1);
	    incount = 0;
            otcount = 0;
	    num_bytes =0;
	    strcpy(command, ";IN?;");
	    viWrite(ssp, command, 10, &RTCount); //10 bytes
	    viGetAttribute(ssp, VI_ATTR_ASRL_AVAIL_NUM, &num_bytes);
	    while(num_bytes < 11)
	    {
			if(num_bytes < 5)
			{
	         		  viWrite(ssp, command, 10, &RTCount);
			}
			viGetAttribute(ssp, VI_ATTR_ASRL_AVAIL_NUM, &num_bytes);  
			viRead (ssp, Databuf, num_bytes, &RTCount);
            }
		    viFlush (ssp, VI_WRITE_BUF);
		    viFlush (ssp, VI_READ_BUF);
			Databuf[RTCount] = '\0';
			packetdata =  strtok(Databuf,";");

 when program sending command ;IN?; it's gets some data. but sometimes buffer is empty. and i added while loop for checking num_bytes for received data.

may be i can remove this while loops and use some VISA attributes? for waiting received data?

thanks