[Bug libc/26022] valgrind gives me error when fwprintf in stderr

["carlos at redhat dot com" <sourceware-bugzilla@sourceware.org>]

https://sourceware.org/bugzilla/show_bug.cgi?id=26022

Carlos O'Donell <carlos at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |carlos at redhat dot com
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |INVALID

--- Comment #1 from Carlos O'Donell <carlos at redhat dot com> ---
Freeing streams during application shutdown is difficult because detached
threads may be writing to unbuffered streams.

As such, stderr, and any other unbuffered streams are untouched during process
shutdown and are not freed by the resource freeing API that glibc exposes for
use by external allocation trackers.

That is to say that __libc_freeres() the public API which glibc uses to expose
resource freeing, will not free unbuffered streams to allow any last minute
writes.

Since stderr starts as unbuffered it is not freed. You can make stderr
buffered, and subject to freeing like this: setvbuf (stderr, NULL, _IOLBF, 0);

Valgrind should probably have a suppresion entry added for stderr because it's
a common stream to be used by applications.

I've filed a Valgrind bug here:
https://bugs.kde.org/show_bug.cgi?id=421931

Please feel free to follow up there if you think it needs an update or you want
to give a +1 regarding your use case.

I'm marking this RESOLVED/INVALID for glibc.

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