Read serial data without high CPU use

Question

I want to read messages sent from an Arduino via the FTDI (serial) interface in a simple C or C++ program under Linux. The Arduino sends a two character \'header\', a command by

Answer 1

The OP has probably long since solved this, but for the sake of anyone who gets here by google:

#include <sys/poll.h>

struct pollfd fds[1];
fds[0].fd = serial_fd;
fds[0].events = POLLIN ;
int pollrc = poll( fds, 1, 1000);
if (pollrc < 0)
{
    perror("poll");
}
else if( pollrc > 0)
{
    if( fds[0].revents & POLLIN )
    {
        char buff[1024];
        ssize_t rc = read(serial_fd, buff, sizeof(buff) );
        if (rc > 0)
        {
            /* You've got rc characters. do something with buff */
        }
    }
}    

Make sure the serial port is opened in nonblocking mode as poll() can sometimes return when there are no characters waiting.