poll() system call not returning when the socket is closed locally

manjub · 09-29-2010, 05:53 AM

we have a multi threaded program on Linux where one thread is waiting on poll() system call with event set to POLLIN, & another thread has closed the same socket fd (which is passed to poll) , but the poll() did not return, is this the expected behavior?

From man page of poll we found that the poll should return POLLNVAL if the socket fd is closed, is my understanding correct or is there any bug in the poll()?

In Solaris we observed that the poll system call is returning with POLLNVAL if the socket is closed.

srinathduraisamy · 09-29-2010, 07:25 AM

Hi,

Normally, if socket fd passed for poll is closed, then poll should return positive value for the socket's EOF.

manjub · 09-29-2010, 10:28 PM

yes we are also expecting an positive value to be returned from poll(), But it is not exiting only!!!
Is this poll() bug free in all versions of LINUX??
We are using 2.6.18-194.el5 kernel release.

srinathduraisamy · 09-30-2010, 12:37 AM

If what every you mentioned was your requirement. You can use select system call instead of poll.

Most people will suggest select over poll.