2016-03-02 15:44+0100, Paolo Bonzini:
> On 02/03/2016 13:57, Radim Krčmář wrote:
>> 2016-03-01 22:29+0100, Paolo Bonzini:
>>> On 29/02/2016 19:53, Andrew Jones wrote:
>>>> + errors=$("${@}" 2>&1 1>&${stdout} | tee >(cat - 1>&2); exit ${PIPESTATUS[0]})
>>>
>>> Whoa! :) So stdout goes to {stdout} and from there to the real stdout;
>>> stderr instead is tee'd to stderr and $errors.
>>
>> Yeah. :)
>>
>>> Is the "tee" and "cat" necessary? Can you just use printf somewhat like:
>>
>> They are, if you want want to improve chances of getting the original
>> order of stdout and stderr.
>
> Getting the original order can't really work if you use separate file
> descriptions.
Yes, there is no "true" order ... my concern is about transparency:
tee delays stderr much less than if we buffered stderr until QEMU has
finished, so mixed stdout/stderr has better chance of being visible in
sans-wrapper order.
> I'm not sure how you would have something on stderr, except on the very
> last line? The idea being that 1) the test only writes to stdout 2)
> QEMU only writes to stderr 3) QEMU exits after writing to stderr. If
> this is true, the proposed assignment/printf pair works just fine.
QEMU prints some warnings without immediately exiting, e.g.
warning: host doesn't support requested feature: CPUID.01H:ECX.vmx [bit 5]
So it's possible that stdout is printed after stderr. Preserving the
visible output could be less confusing in these rare cases. I agree
with the late printf if you think that the ugly code is not worth it.
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