Re: [Qemu-devel] [PATCH] suppress 'warn_unused_result' warning

[Anthony Liguori <anthony@codemonkey.ws>]

Daniel P. Berrange wrote:
> On Mon, May 11, 2009 at 11:16:24AM -0500, Anthony Liguori wrote:
>   
>> Any system call can return EINTR just about.  It's not just read/write.
>>     
>
> For many system calls you can have them auto-restarted after EINTR
> by using sigaction() with the SA_RESTART flag. IIRC read/write/poll 
> won't support restarts in this way though, because of the problem of
> partial data read/writes and partial timeouts for poll meaning you
> can't auto-restart them without app developer help
>   

SA_RESTART in theory is supposed to cover everything IIUC.  I don't know 
that that's true in Linux in practice though.  I definitely don't know 
about other Unices.

I don't think there's a standard way to know which syscalls would be 
restarted and which ones would.  If you expect EINTR, I think you pretty 
much have to handle it everywhere.

Regards,

Anthony Liguori

> Daniel
>