有几种可能的方法 . 如果程序最终将定时多个i / o操作， select() 是明智的选择 .

但是，如果唯一的输入来自此i / o，则选择非阻塞i / o和时序是一种简单的方法 . 我已经将它从单字符i / o扩展到多字符，使其成为一个更普遍的完整示例：

#include

#include

#include

#include

int main(void)

{

int fd = open("/dev/ttyS0", O_RDWR | O_NOCTTY | O_NDELAY); // sometimes "O_NONBLOCK"

char buf[10];

int done = 0, inbuf = 0;

struct timeval start, now;

gettimeofday (&start, NULL);

while (!done)

{

int bytesRead = read(fd, &buf[inbuf], sizeof buf - inbuf);

if (bytesRead < 0)

{

error_processing_here();

continue;

}

if (bytesRead == 0) // no data read to read

{

gettimeofday (&now, NULL);

if ((now.tv.sec - start.tv_sec) * 1000000 +

now.tv.usec - start.tv_usec > timeout_value_in_microsecs)

{

done = 2; // timeout

continue;

}

sleep(1); // not timed out yet, sleep a second

continue;

}

inbuf += bytesRead;

if (we have read all we want)

done = 1;

}

if (done == 2)

timeout_condition_handling();

close(fd);

return 0;

}