poll() and read() “resource temporarily unavailable”

Question

I have a problem about read() with "resource temporarily unavailable". I'm using PIPE as a IPC between threads.

In my program, reading thread checks if PIPE has a data using poll() , and then read() from PIPE. But, sometimes read() returns -1 with following error.

resource temporarily unavailable

I have no idea why read() return error after poll() check.

Answer 1

您可能已将管道fd设置为非阻塞模式O_NONBLOCK，并且在空文件上进行读取时，它将返回EAGAIN。