Problem detecting data no Serial Port

try this code , it check how much char are in the uart buffer

# include "altera_avalon_uart.h"# include <fcntl.h># include <unistd.h># include "priv/alt_file.h"

int getUartBufferCnt()

{

//alt_fd* fd=&alt_fd_list[fdterm];

//fd is the uart&#39;s file discreptor

alt_avalon_uart_dev* dev = (alt_avalon_uart_dev*) fd->dev;

int bufferCnt=dev->rx_end-dev->rx_start;

if(bufferCnt<0)

bufferCnt+=ALT_AVALON_UART_BUF_LEN;

return bufferCnt;

}