Hi, Nikodemus
Today I think out another way to solve the SBCL connection timeout issue, I wrap a SB-EXT:WITH-TIMEOUT on SB-BSD-SOCKET:SOCKET-CONNNECT [1], and the result work seems working well:
* (time (ignore-errors (usocket:socket-connect "8.8.8.8" 80 :timeout 3)))
Evaluation took: 3.010 seconds of real time 0.010234 seconds of total run time (0.009223 user, 0.001011 system) 0.33% CPU 32 lambdas converted 6,608,582,602 processor cycles 916,672 bytes consed
NIL #<USOCKET:TIMEOUT-ERROR {1002F34851}>
Do you think this is an acceptable solution?
--binghe
[1] http://trac.common-lisp.net/usocket/changeset/589
在 2011-3-28，04:26， Nikodemus Siivola 写道：
2011/3/27 Chun Tian (binghe) binghe.lisp@gmail.com:
Well, I think the TIMEOUT keyword arguments on SOCKET-CONNECT currently has following meanings:
- When doing TCP work, it means a "connection timeout";
- When doing UCP work, it sets the default "read timeout" (because "connection timeout" is meaningless for UDP);
For SBCL backend at least this is not correct.
There :TIMEOUT is a read timeout for any single blocking read from the socket. Connections and writes are unaffected -- though SBCL changes may apply the timeouts to writes as well.
Waiting for a connection is not affected -- but adding support for that is pretty easy.
Sidenote: I haven't really looked at usocket's SBCL backend beyond SOCKET-CONNECT prior to this, but a quick peek shows that it's pretty cavalier about using SBCL internals. This is not good. Internals _will_ change, and then usocket will break. Specifically, SB-UNIX package is an internal implementation package -- using it is bad. SB-POSIX is the supported POSIX api. Some SB-FOO::BAR stuff in there as well. :/
Cheers,
-- Nikodemus