Hi Elias,
if have implemented the *poll() *as a non-default alternative to
*select() *in *APserver*.
Unfortunately I can't reproduce the problems that I had earlier (they
occurred in the middle
of development), but I would be surprised if*poll()* would differ
from*select() *in that respect.
Anyhow, I made the transport protocol towards *APserver* configurable so
the user can
choose what she feels fit.
A unique filename is a nice idea but does not work because *apl* and the
*APs* would have no
reliable way to figure it.
I am also not very comfortable with deleting files automatically. This
should be kept
to the absolutely necessary minimum. I really believe that TCP on
localhost is a cleaner
choice on systems that do not support abstract AF_UNIX sockets. SVN 392.
/// Jürgen
On 07/24/2014 01:59 PM, Elias Mårtenson 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 <mailto: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
<mailto: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
