Re: new compiler warnings

On 10/18/2011 09:03 AM, Kevin Grittner wrote:
> Jeff Davis wrote:
>
>> I'm not sure if these can/should be fixed or not, but here are the
>> compiler warnings I'm getting on gcc and clang on ubuntu 11.10 with
>> -O2.
>
>> elog.c: In function ‘write_pipe_chunks’:
>> elog.c:2479:8: warning: ignoring return value of ‘write’, declared
>> with attribute warn_unused_result [-Wunused-result]
>> elog.c:2488:7: warning: ignoring return value of ‘write’, declared
>> with attribute warn_unused_result [-Wunused-result]
>> elog.c: In function ‘write_console’:
>> elog.c:1797:7: warning: ignoring return value of ‘write’, declared
>> with attribute warn_unused_result [-Wunused-result]
>
>> common.c: In function ‘handle_sigint’:
>> common.c:247:4: warning: ignoring return value of ‘write’, declared
>> with attribute warn_unused_result [-Wunused-result]
>> common.c:250:4: warning: ignoring return value of ‘write’, declared
>> with attribute warn_unused_result [-Wunused-result]
>> common.c:251:4: warning: ignoring return value of ‘write’, declared
>> with attribute warn_unused_result [-Wunused-result]
>> In file included from mainloop.c:425:0:
>
> These we are getting only because of a stubborn insistence on coding
> to the current implementation rather than the API. It's not that
> much code to code to the API instead. I've already offered to
> provide the (trivial) patch for this if there is buy-in on the idea
> of coding to the API.
>
> The argument against is that no implementer of the API would ever
> exercise the freedom the documented API gives them to do *part* of a
> write to disk and return to the caller the number of bytes written
> and then allow a subsequent write request to continue the output. I
> think that the rise of virtual machine environments in big shops
> provides a fairly obvious reason someone might want to do that.
>
>

There are non-disk uses of write() where partial writes are legitimate
(e.g. pipes under some circumstances on Linux).

It is a pity we can't just tell the compiler to turn off the warning in
a particular case.

cheers

andrew