[RFC] 4950302: (fs spec) Random write produces different results on Linux vs Windows from same .class

[Brian Burkhalter]

> On Nov 21, 2019, at 2:00 PM, David Lloyd <david.lloyd at redhat.com> wrote:
> 
>>> According to [1] RWF_APPEND is supposed to be since Linux 4.16. Am I missing something?
>>> 
>>> Thanks,
>>> 
>>> Brian
>>> 
>>> [1] https://manpages.debian.org/testing/manpages-dev/preadv2.2.en.html
>> 
>> It probably has more to do with the glibc (and associated header
>> files) in use.  You consider directly defining the symbols if a
>> feature test macro check doesn't satisfy?
> 
> You *might* consider...


You are probably correct, but RWF_APPEND does not show up in the Ubuntu 18.04.3 man page [1] but is in 19.04 [2]. I did verify however that pwritev2(2) with RWF_APPEND does have the desired behavior in Ubuntu 19.04. The symbols had to be enabled by defining __USE_GNU:

#define __USE_GNU
#include <sys/uio.h>

Thanks,

Brian

[1] http://manpages.ubuntu.com/manpages/bionic/man2/readv.2.html
[2] http://manpages.ubuntu.com/manpages/disco/man2/readv.2.html
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