[erlang-questions] Yaws's "sendfile" linked-in driver : "stealing control of fd" error

Steve Vinoski vinoski@REDACTED
Mon Apr 18 02:45:29 CEST 2011

On Sun, Apr 17, 2011 at 5:23 PM, zabrane Mikael <zabrane3@REDACTED> wrote:
> Hi OTP team & Steve,
> I'm using the "sendfile" (thanks to Steve Vinoski) linked-in driver
> borrowed from "Yaws"
> in one of my pet project.
> Today, I noticed this strange error:
> =ERROR REPORT==== 17-Apr-2011::20:49:18 ===
> driver_select(0x0000000000000c31, 24, ERL_DRV_WRITE, 1) by
> sendfile_drv driver #Port<0.3121> stealing control of fd=24 from
> output driver tcp_inet #Port<0.10029>

I can't speak authoritatively about exactly what causes this, but I
can say that most of the times I've seen this were when serious
problems were occurring -- most often prior to a fatal VM crash, but I
think it's also occasionally occurred when the VM was shutting down
normally. It's been awhile since I've seen it at all, though.

> Could someone please tell me what's the aim of this C function?
> Should I consider this as an error or can I forget about it?

Someone familiar with the "steal" code should correct me if I'm wrong
(please!), but I would recommend treating this as an error. Can you
provide details about what your app is doing when it causes this error


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