Re: open - resource temporarily unavailable

[Sven Joachim <svenjoac@gmx.de>]

On 2016-06-16 21:46 +0600, Andrew P. Cherepenko wrote:

> Hello list,
>   'open()' for creating file sometimes returns an error:
>     couldn't open "myfile.txt": resource temporarily unavailable
>     either in background process or interactively (ex: in Emacs when
> trying to save a file).

Are you sure that it's opening the file which fails in that way, and not
writing to it?  Because, according to the manpages, EAGAIN is a possible
error in write(2), but not in open(2).  Quoting the write() manpage:

,----
| EAGAIN The file descriptor fd refers to a file other than a socket
|        and has been marked nonblocking (O_NONBLOCK), and the write
|        would block.  See open(2) for further details on the O_NON‐
|        BLOCK flag.
`----

> system: Debian 8.5
> with kernel: linux-image-3.16.0-4-amd64
> and systemd 215-17+deb8u4
>
> Is that concerned with some imposed limits on the kernel resources ?

Probably not.  The only limit that should play a role here is the number
of file descriptors, and the error would be EMFILE ("Too many open
files") rather than EAGAIN.

Cheers,
       Sven