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From: "siddhesh at sourceware dot org" <sourceware-bugzilla@sourceware.org>
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Subject: [Bug libc/29417] poll() declared with write-only fds
Date: Wed, 27 Jul 2022 18:40:24 +0000
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https://sourceware.org/bugzilla/show_bug.cgi?id=3D29417

--- Comment #4 from Siddhesh Poyarekar <siddhesh at sourceware dot org> ---
(In reply to Florian Weimer from comment #3)
> What would be problematic if GCC decided to eliminate stores to the fds
> array, assuming that it will be overwritten completely. But I don't think
> the specification for write_only allows that. (write_only is perhaps
> misnamed.)

The compiler cannot eliminate stores because it doesn't know if poll will
overwrite the object.  That said, I wouldn't stick out my neck and say that=
 the
write_only attribute is absolutely correct in this context; the structure d=
oes
need to be read further down ithe stack n the syscall.

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