# RE: \[PATCH\] compat: Add another rudimentary poll() emulation

- From: Peter Kjellerstedt \<hidden\>
- Date: 2016-06-15 22:48:52 
- List: git
- Page: https://ratatoskr.run/git/2016/06/7465718
- Thread: https://ratatoskr.run/git/2016/06/7465679/t.md

```text
> -----Original Message-----
> From: <redacted> [mailto:<redacted>] On
> Behalf Of Erik Faye-Lund
> Sent: den 27 maj 2010 16:44
> To: Marko Kreen
> Cc: Jonathan Nieder; Jonathan Callen; <redacted>;
> mduft@gentoo.org; Sverre Rabbelier; Michael J Gruber; Johannes Sixt;
> msysGit
> Subject: Re: [PATCH] compat: Add another rudimentary poll() emulation
> 
> On Thu, May 27, 2010 at 4:32 PM, Marko Kreen [ref] wrote:

[cut]

> > Ah, ok.  I though this is the nfds for select().  In this case it can
> > still fail, as nfds=1 for poll() can still go over FD_SETSIZE for
> > select() if the fd value is big enough.  On non-windows, that is.
> 
> I don't quite get where one would get a fd that's value is FD_SETSIZE
> or above from. I mean, FD_SETSIZE would have to be the maximum value
> of a file descriptor, or else you risk open() or socket() returning
> file descriptors that cannot be select()'ed. Which would just be
> insane, no?
> 
> --
> Erik "kusma" Faye-Lund

That is exactly how e.g. Linux works. If your application can have more 
than 1024 file descriptors open simultaneously, you are restricted to 
use poll() as you risk having a file descriptor with a value >= 1024.
And using FD_SET() with a file descriptor >= 1024 will trash memory...

//Peter
```