dd -- bs>=2G, error writing to /dev/null - possible bug? (win7; coreutils 8.26)

[Marco Atzeri]

On 12/03/2017 12:39, Corinna Vinschen wrote:
> On Mar 12 00:33, Josef Frank wrote:
>>
>> Dear all,
>>
>>
>> dd utility has problems to write to /dev/null with bs>=2^31,
>> while bs<2^31 is ok.
>>
>> Increasing bs further to 2^33 leads to extended error message
>>
>> For description see below
>
> Thanks for the testcase.  It's a combination of two bugs:
>
> - At a crucial point in write(2), Cygwin used an int variable where
>   it should have used a ssize_t variable.  This fouled up the return
>   value for lengths >= 2^31.
>
> - When writing to the Windows NUL device, NtWriteFile only returns the
>   lower 32 bits od the number of bytes written.  This fouls up the
>   return value of write(2) for lengths >= 2^32.
>
> I fixed the first problem and created a workaround for the second.
>
> I uploaded new developer snapshots to https://cygwin.de/snapshots/
> Please give 'em a try.

May be
https://cygwin.com/snapshots/

>
>
> Thanks,
> Corinna

Cheers
Marco


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