Subject: Re: poll() emulation in git

From: Paolo Bonzini <[email-masked]>
Date: Wed, 05 Sep 2012 14:05:21 +0200

Il 05/09/2012 13:24, Joachim Schmitz ha scritto:
> However: this poll implementation, while compiling OK, doesn't work properly.
> Because it uses recv(...,MSG_PEEK), it works on sockets only (returns ENOTSOCK on anything else), while the real poll() works on all
> kind if file descriptors, at least that is my understanding.

Actually recv(...,MSG_PEEK) on most Unix variants works on non-sockets
too.  The trick is taken from GNU Pth in turn.

> Here on HP NonStop, when being connected via an non-interactive SSH, we get a set of pipes (stdin, stdout, stderr) instead of a
> socket to talk to, so the poll() just hangs/loops.

Does your system have a working FIONREAD ioctl for pipes?

> As git's implementation is based on ('stolen' from?) gnulib's and still pretty similar, CC to the gnulib list and Paolo
> 
> Any idea how this could get solved? I.e. how to implement a poll() that works on non-sockets too?
> There is some code that pertains to a seemingly similar problem in Mac OS X, but my problem is not identical, as that fix doesn't
> help.

Paolo