[musl] Re: Tweaking the program name for <err.h> functions

[Florian Weimer]

* Zack Weinberg:

> On Tue, Mar 12, 2024, at 9:54 AM, Florian Weimer wrote:
>>> Doing this would break many programs, such as:
>>> - most of coreutils, e.g. programs like ls, cat or head, since they
>>>   always `close` their input and output descriptors (when they've
>>>   written or read something) to make sure to diagnose all errors
>>
>> A slightly better way to do this is to do fflush (stdout) followed by
>> error checking on close (dup (fileno (stdout))).
>
> Does that actually report delayed write errors?  As you have it,
> the close() just drops the fd created by the dup(), the OFD is
> still referenced by fd 1 and therefore remains open.

I don't think the VFS close action is subject to reference counting.
Otherwise the current coreutils error checking wouldn't work because in
many cases, another process retains a reference to the OFD.

Thanks,
Florian