Re: [PATCH v5 3/8] convert: Split start_multi_file_filter into two separate functions

> On Tue, Apr 11, 2017 at 10:01:02PM +0200, Lars Schneider wrote:
>
>>> If you initialize errno to 0 right before a syscall, then yes, you can
>>> trust it without checking the return value of the syscall. I wouldn't
>>> trust it before calling more complicated functions, though. Not even
>>> xwrite(), which may see EINTR and keep going (which is OK for checking
>>> for EPIPE, but not checking generally for errno values).
>> Should we remove all the errno checks here as we don't have any direct
>> "write" etc syscalls anyways then?
> Yeah, you should be trusting the return value from the various
> sub-functions. Usually you'd check "errno == EPIPE" only when you saw an
> error return but you want to _ignore_ EPIPE. This is what
> filter_buffer_or_fd() is doing.
>
> But the code here is the opposite case. It definitely wants to treat
> EPIPE as an error. But that should be happening already because any
> EPIPE we get would come with an error-return from one of the
> packet_write() functions.
>
> So I would say that "err || errno == EPIPE" here can just become "err",
> and ditto in apply_multi_file_filter().