[Libevent-users] SO_LINGER option for sockets created by evhttp

[Ilya Martynov]

Hi,

I wonder if anybody could elaborate what is the reason for setting
SO_LINGER option for sockets created by evhttp. I mean this part of code
inside of http.c:

static int
bind_socket_ai(struct addrinfo *ai)
{
         ...
         linger.l_onoff = 1;
         linger.l_linger = 5;
         setsockopt(fd, SOL_SOCKET, SO_LINGER, (void *)&linger,
sizeof(linger));
         ...
}

If I'm reading the documentation correctly at least for Linux this
makes close() on the socket to block what probably not a very good thing
in programs based on libevent. From
http://linux.about.com/od/commands/l/blcmdl7_socket.htm:

SO_LINGER
     Sets or gets the SO_LINGER option. ... When enabled, a close(2) or
shutdown(2) will not return until all queued messages for the socket
have been successfully sent or the linger timeout has been reached.
Otherwise, the call returns immediately and the closing is done in the
background.

-- 
Ilya Martynov,  ilya at iponweb.net
CTO IPonWEB (UK) Ltd