Sorry, not POLLPRI. It's POLLERR or POLLHUP. You can see how it's done here:
https://github.com/lokedhs/gnu-apl-mode/blob/master/native/UnixSocketListener.cc#L125 Regards, Elias On 24 July 2014 19:59, Elias Mårtenson <loke...@gmail.com> wrote: > I believe if you use poll() rather than select(), you should be able to > detect this state. Add a listener for the event POLLPRI. > > Regards, > Elias > > > On 24 July 2014 19:57, Juergen Sauermann <juergen.sauerm...@t-online.de> > wrote: > >> Hi Elias, >> >> given that hardly anybody uses shared variables these days this discussion >> is more on the theoretical side than of practical relevance. >> >> For that reason I would like the solution to be as simple as possible. >> The extra things needed as you state below make things more complicated >> and raise new problems, e.g. unlink the socket while it is still used and >> the like. >> >> Also I have not found a reliable way to figure if a connection is closed >> or not. >> For example if I do *kill -9* of a process that is connected to >> *APserver* then >> *APserver* does not detect this in its *select()* loop. >> >> /// Jürgen >> >> >> >> On 07/24/2014 01:34 PM, Elias Mårtenson wrote: >> >> I did not know about that feature. Interesting. Also interesting that >> it's not supported on OSX. >> >> That said, I still think Unix domain sockets are good in this case. >> There are just a few things that needs to be done in order to make them >> solid. I think I did most of those things in the native code for the Emacs >> mode. >> >> These things include: >> >> - Call unlink() on the socket file before creating it (in case there >> is one lingering from before). >> - Call unlink() on the socket when shitting down (we want everything >> to be clean after shutdown). >> - When automatically starting the backend (as opposed to manually >> creating it), compute the filename so that it's reasonably unique. I.e. >> append the process ID to it or something. >> >> What do you think of this? >> >> Regards, >> Elias >> >> >> On 24 July 2014 19:26, Juergen Sauermann <juergen.sauerm...@t-online.de> >> wrote: >> >>> Hi Elias, >>> >>> the idea is this: >>> >>> man 7 unix says: >>> >>> *abstract: an abstract socket address is distinguished by the fact* >>> * that sun_path[0] is a null byte ('\0'). The socket's >>> address in* >>> * this namespace is given by the additional bytes in sun_path >>> that are* >>> * covered by the specified length of the address >>> structure. (Null* >>> * bytes in the name have no special significance.)* >>> >>> So I *memset()* the entire socket address first and then copy the name >>> to *sun_path,* >>> but starting at *sun_path[1]* so that *sun_path[0]* remains *0 *(making >>> it an abstract >>> socket). >>> >>> man 7 unix also says: >>> >>> * The abstract socket namespace is a nonportable Linux extension.* >>> >>> That's why I *#define ABSTRACT_OFFSET* to 1 if your OS supports it and >>> you can change it to 0 if not. In the latter case you have to provide a >>> file >>> */tmp/GNU-APL/APserver* manually with proper permissions. >>> >>> This file is having the file permissions that you were after earlier. I >>> am >>> not creating that file because I expect more problems with it than >>> benefits >>> (who owns it, who installs it, what if one user creates it with wrong >>> permissions etc.). >>> >>> My general feeling is that TCP on localhost is much cleaner and maybe I >>> should make >>> that the default. >>> >>> /// Jürgen >>> >> >> >> >
