Re: [Caml-list] Unix.Unix_error(31, "write", "") raised from format.ml!? This is not right.

[Arlen Cuss <celtic@sairyx.org>]

I eat my words. :( I was doing the Printexc.get_backtrace () call
immediately after a printf statement (printing information about the
exception), so I got a stack for that instead!

Sorry for the noise!

Arlen

On Tue, 2011-03-08 at 13:17 +1100, Arlen Cuss wrote:
> Hi all,
> 
> I'm getting bizarre errors in a program which multiplexes on 50-100
> sockets (some Unix domain, some TCP), where an error will apparently
> occur in "write", but the entire backtrace is limited to 'format.ml':
> 
> backtrace: Raised at file "format.ml", line 194, characters 15-26
> Called from file "format.ml", line 420, characters 8-33
> Called from file "format.ml", line 435, characters 6-24
> 
> The backtrace does describe a correct path through format.ml:
> 
> 194    | _ -> raise Empty_queue
> 
> 420   match peek_queue state.pp_queue with
> 
> 435   try advance_loop state with
> 
> It's hard to determine what's going on, because for some reason the
> backtrace is limited to this file, and none of my own code. I'm a bit
> lost as to how these errors are being raised:
> 
> Exception Unix.Unix_error(31, "write", "") occurred
> Exception Unix.Unix_error(56, "write", "") occurred
> 
> Both are occurring with the same reported backtrace; the former is Unix
> error EMLINK (too many links), the latter EISCONN (socket is connected);
> the strange thing is that *neither* of these errors should be throwable
> on a write() call!
> 
> I've ensured I'm correctly compiling with debug info, so I'm a bit lost.
> I can only assume a sprintf or similar call somewhere is going haywire.
> 
> Anyone seen anything like this before?
> 
> Best,
> Arlen
> 
>