C 中的串行端口问题，Mac OS X 10.6.8

我已经运行以下代码，并且它一直运行。但是，它似乎没有等待任何输入，而我从缓冲区中获得的唯一输出是" 377"，我一直在阅读POSIX操作系统的串行编程指南，并尝试使用那里提供的一些建议，但是我认为我的配置中的某些东西可能正在将其抛弃。任何想法都将不胜感激。

#include <iostream>
using namespace std;
#include <stdio.h>   /* Standard input/output definitions */
#include <string.h>  /* String function definitions */
#include <unistd.h>  /* UNIX standard function definitions */
#include <fcntl.h>   /* File control definitions */
#include <errno.h>   /* Error number definitions */
#include <termios.h> /* POSIX terminal control definitions */

int open_port() {
    int fd; //Descriptor for the port
    fd = open("/dev/tty.usbmodemfa141", O_RDWR | O_NOCTTY | O_NDELAY);
    if (fd == -1) {
        cout << "Unable to open port. n";
}
else {
        cout << "Port opened.n";
}
cout << "Descriptor in open:";
cout << fd;
cout << "n";
return fd;
}
int configure_port (int fd) {
struct termios options;
tcgetattr(fd, &options);
cfsetispeed(&options, B9600);
cfsetospeed(&options, B9600);
options.c_cflag &= ~PARENB;
options.c_cflag &= ~CSTOPB;
options.c_cflag &= ~CSIZE;
options.c_cflag |= CS8;
options.c_cflag |= (CLOCAL | CREAD);
tcsetattr(fd, TCSANOW, &options);
cout << "Port configured.n";
return (fd);
}
void read_data(int fd) {
cout << "Reading data from: ";
cout << fd;
cout << "n";
char buffer;
buffer = fcntl(fd, buffer, 0);
cout << "Buffer: ";
cout << buffer;
cout << "n";
}
int main (int argc, char * const argv[]) {
int fd; //Descriptor for the port
fd = open_port();
configure_port(fd);
cout << "Descriptor: ";
cout << fd;
cout<< "n";
read_data(fd);
cout << "Data read.";
return 0;
}