I'm not sure, but I will say that the WServer implementation uses
`boost::asio` no matter in which platform you are. The linking takes place
in the wthttpd connector, which is already linked in the .so or in the .dll
in your case or whatever the file extension is for statically linked
libraries in Windows (by the way, I use the wthttpd connector, neither
isapi nor fcgi).
So, you have no way of knowing whether `boost::asio` is being linked or not
looking at your manually added libraries, because the libraries needed by
your connector are already linked in the connector object file itself (I'm
not an expert, though, but I would say yes to that).
My Wt version is 3.3.4 and no, I haven't written any explicit code.To try
to convince you further, the string I receive, "Address already in use",
doesn't appear in the source code of Wt (WServer interface or connector
--which implements some functions of WServer, so, linking against different
connectors, get different implementation of those WServer's delegated
functions).
However, the string "Error occurred when binding" does appear in
http/Server.C, so, the exception is being captured by Wt in the wthttp
connector source code, and after printing that line, it prints the
exception message ("Address already in use") carried on the `boost`
exception thrown by the `tcp_endpoint` object when trying to connect to the
configured port.
On 31 October 2016 at 16:36, K. Frank <kfrank2...@gmail.com> wrote:
> Hi Aarón!
>
> Thank you for your answer.
>
> On Mon, Oct 31, 2016 at 9:36 AM, Aarón Bueno Villares
> <abv15...@gmail.com> wrote:
> > In my case (Ubuntu Server 14.04), when launching a second server instance
> > (from terminal of course) it throws me an error:
>
> Do you know what version of Wt you are using? (As a reminder, I am
> using a copy of 3.3.3 that I built a couple of years ago.)
>
> > [2016-Oct-31 14:31:17.746221] 8337 - [info] "WServer/wthttp:
> > initializing built-in wthttpd"
> > [2016-Oct-31 14:31:17.747020] 8337 - [error] "wthttp: Error occurred
> > when binding to ::1:11000
> > bind: Address already in use"
> > Error (asio): bind: Address already in use
>
> First, am I right that the error appears in the console log (without
> you writing any explicit code)?
>
> Is the error otherwise reported? Are you calling WRun or are you
> working with WServer directly? If you're working with WServer, are
> you calling WServer::start(), and, if so, is it returning false?
>
> Is any kind of c++ exception being thrown, in particular, a
> WException or a WServer::Exception?
>
> > So, I conclude that it's the boost::asio library who throws an exception
> > with that message. `Wt` just displays it and the server launching is
> > stopped.
>
> Oddly enough, it's not obvious that my Wt application is using boost::asio.
> (Although maybe it is.)
>
> In my setup, I link statically to about half a dozen boost libraries (boost
> 1.57, by the way), for example, -lboost_program_options-mgw49-1_57
> and -lboost_thread-mgw49-mt-s-1_57. I don't see anything that looks
> like it would be asio. (Because io, in general, and sockets, in
> particular,
> are os-dependent, I wouldn't expect boost::asio to be a header-only
> library.) I do link to something called -lboost_system-mgw49-1_57.
> Maybe boost::asio is hiding in there.
>
> > If your server runs and waits the port is free, or it's able to bind more
> > than one process to a same port, but in any case it's not halted, it
> must be
> > an OS-specific behaviour (otherwise, `boost::asio` should throw an
> > exception).
>
> I've done only a little hands-on winsock programming, and it's certainly
> not fresh in my mind. But I would have expected (winsock's version of)
> bind to fail with some sort of "port in use" error. So what you see on
> linux is what I would have expected.
>
> Any further thoughts would be appreciated. And it would be great if
> a windows / winsock expert could chime in on what behavior would
> normally be expected on windows.
>
> (By the way, I do use winsock, linking with -lws2_32 and -lwsock32.)
>
>
> I appreciate your help.
>
>
> K. Frank
>
>
> > On 31 October 2016 at 14:23, K. Frank <kfrank2...@gmail.com> wrote:
> >>
> >> Hello List!
> >>
> >> I have two questions about WServer error handling:
> >>
> >> (This is wt-3.3.3 compiled with mingw-w64 on windows 7.)
> >>
> >> First, I see no errors when trying to start a wthttpd server on an
> >> already bound port. What behavior should I expect?
> >>
> >> Details: I've built a "minimal" wthttpd server -- it just servers
> >> html files, so no WApplication. I run two copies of it at the
> >> same time, both launched with "--http-port=80". The first
> >> copy works, services http connections, and serves the html
> >> pages. The second copy reports no errors, and doesn't receive
> >> any http requests -- presumably because all of the port-80 traffic
> >> goes to the first copy.
> >>
> >> My understanding is that the first copy binds to port 80, and
> >> everything works. I would expect that the second copy fails
> >> to bind to port 80, which would seem to be to be an error
> >> condition. But the second copy reports no errors.
> >>
> >> Here is the relevant code:
> >>
> >> int main (int argc, char *argv[]) {
> >> try {
> >> WServer server;
> >> server.setServerConfiguration (argc, argv);
> >> if (server.start()) WServer::waitForShutdown();
> >> else cout << "error on server.start()" << endl;
> >> }
> >> catch (const WException& e) {
> >> cout << "WException caught, e.whatA() = " << e.what() << endl;
> >> }
> >> return 0;
> >> }
> >>
> >> Here's how I launch both copies:
> >>
> >> minimal_wt3 --http-address=0.0.0.0 --http-port=80
> >> --deploy-path=/dummy --docroot=.
> >>
> >> A little more detail: If I kill the first copy of the wthttpd server
> (and
> >> just leave the second running, without restarting it or anything), the
> >> second copy now responds to incoming connections, serves the
> >> html pages, etc. Is this expected?
> >>
> >> Here;s the output from the second copy:
> >>
> >> Option no-compression is implied because wthttp was built without
> >> zlib support.
> >> [2016-Oct-31 08:21:09.352845] 4236 - [info] "config: reading Wt
> >> config file: c:/witty/wt_config.xml (location = '')"
> >> Option no-compression is implied because wthttp was built without
> >> zlib support.
> >> [2016-Oct-31 08:21:09.372845] 4236 - [info] "WServer/wthttp:
> >> initializing built-in wthttpd"
> >> [2016-Oct-31 08:21:09.372845] 4236 - [info] "wthttp: started
> >> server: http://0.0.0.0:80";
> >> 127.0.0.1 - - [2016-Oct-31 08:22:34.961484] "GET /nonexistant.html
> >> HTTP/1.1" 404 85
> >>
> >> Note, between the last two lines -- that is, before the line:
> >>
> >> 127.0.0.1 - - [2016-Oct-31 08:22:34.961484] "GET /nonexistant.html
> >> HTTP/1.1" 404 85
> >>
> >> I killed the first server. I then browsed to the "nonexistant.html"
> url,
> >> and the second server correctly responds with a 404 (because that
> >> html page doesn't exist).
> >> ...
> >> Thanks.
> >>
> >> K. Frank
>
> ------------------------------------------------------------
> ------------------
> The Command Line: Reinvented for Modern Developers
> Did the resurgence of CLI tooling catch you by surprise?
> Reconnect with the command line and become more productive.
> Learn the new .NET and ASP.NET CLI. Get your free copy!
> http://sdm.link/telerik
> _______________________________________________
> witty-interest mailing list
> witty-interest@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/witty-interest
>
------------------------------------------------------------------------------
Developer Access Program for Intel Xeon Phi Processors
Access to Intel Xeon Phi processor-based developer platforms.
With one year of Intel Parallel Studio XE.
Training and support from Colfax.
Order your platform today. http://sdm.link/intel
_______________________________________________
witty-interest mailing list
witty-interest@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/witty-interest
