Re: non-blocking I/O

[Bastien ROUCARIES]

On Tue, Mar 29, 2011 at 2:08 PM, Bruno Haible <address@hidden> wrote:
> Hi Paolo, Eric,
>
>> prefer to implement {g,s}et_nonblock_flag functions. ...
>> This module can then be used to build a fcntl F_GETFL/F_SETFL
>> implementation, but it is not very important to do so.
>
> Nevertheless in gnulib we try to offer the POSIX APIs, if possible.
>
> There are three APIs for non-blocking I/O on Unix:
>  1) fcntl F_SETFL O_NONBLOCK  (POSIX, SysV)
>  2) fcntl F_SETFL O_NDELAY  (older SysV)
>  3) ioctl FIONBIO  (BSD 4.2)
4) SOCK_NONBLOCKL

Bastien

> According to the include files the support is the following:
>
>  - glibc, MacOS X, FreeBSD, NetBSD, OpenBSD, AIX, HP-UX, IRIX, OSF/1, Solaris,
>    Cygwin, Interix   have all three APIs,
>  - mingw             lacks F_GETFL, O_NONBLOCK, O_NDELAY
>  - BeOS              lacks O_NDELAY, FIONBIO
>  - Haiku             lacks O_NDELAY
>
> So, barring bugs that we find during unit testing, we need
>  - a replacement for fcntl F_SETFL O_NONBLOCK that supports mingw,
>  - extend lib/open.c so that it handles O_NONBLOCK on mingw (presumably
>    by failing, because Win32 does not support non-blocking I/O on
>    regular files).

Or fail silently ?

Bastien
>
> I agree that get/set_nonblocking functions are a good step towards this.
>
> Bruno
> --
> In memoriam Rachel Levy <http://en.wikipedia.org/wiki/Rachel_Levy>
>
>