Re: [PATCH 26/28] Avoid gcc 5.4 warning -Wunused-result

[Jason Gunthorpe <jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>]

On Tue, Sep 13, 2016 at 09:58:56PM +0000, Hefty, Sean wrote:
> > It used to be you could suppress this with (void), however the gcc
> > developers have decided to get rid of that.
> > 
> > So, look closely at each occurrence and decide what to do:
> > - *pingpong: Join the error handling with the if statement directly
> >    above
> > - niegh: read on a timer_fd should never fail, so just use assert.
> >    The assert is compiled out for Release builds so this is no-change
> > - acm: Failure of ucma_set_server_port is detected by a 0 return
> >    so check fscanf and return appropriately. This is no change since
> >    fscanf failure was assumed to have left server_port as 0 (though
> >    I doubt the standard supports that usage)
> > - rsocket: This looks super sketchy. At least lets make the intent
> > clear
> >    with a read_all/write_all wrapper that calls assert. Most likely
> >    this code is wrong..
> >    Mangle the code with failable_fscanf to make it clear, but as with
> >    acm, I don't think the standard supports this usage.
> > 
> > Signed-off-by: Jason Gunthorpe <jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
> 
> For my parts
> 
> Acked-by: Sean Hefty <sean.hefty-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>

Thanks

> The rsocket code is sending a small message between a socketpair to
> notify a service thread that it needs to add a new rsocket to its
> processing.  It could probably check for a failure on the write
> calls and report that back to the caller.  If the read fails, I'm
> not sure what the service thread could do.

In these situations I usually use close on the fd as a synchronous way
to ask the worker thread to exit..

But my comments about being 'wrong' are more to do with not handling
EINTR. If you are not reading from a file, and are doing blocking
reads, then you have to deal with it in the general library case.

Jason
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