Re: riscv32, qemu-user: semi-functional, what goes wrong?

[Chet Ramey]

On 9/12/23 4:46 PM, Andreas K. Huettel wrote:
> Am Dienstag, 12. September 2023, 21:55:13 CEST schrieb Chet Ramey:
> > > run-posixexp
> > > 309d308
> > > < ./posixexp.tests: line 98: syntax error: unexpected end of file
> >
> > Did you remake y.tab.c? And if so, what version of bison did you use?
>
> Not deliberately, but this is 5.2_p15, so if one of the patches touches the 
> source...

All the appropriate patches updated both parse.y and y.tab.c (6, 7, 12,
15).

> riscv32 ~ # bison --version
> bison (GNU Bison) 3.8.2
>
> I just re-ran the bash build, and the log contains a line
> bison -y -d ./parse.y

The reason I ask is that I can reproduce the error message with bash-5.1,
but not bash-5.2.


> > > run-read
> > > warning: please do not consider output differing only in the amount of
> > > warning: white space to be an error.
> > > 47c47
> > > < a
> > > ---
> > > > abcde
> > > 71c71
> > > < 0
> > > ---
> > > > 1
> > > 74c74
> > > < 1
> > > ---
> > > > timeout 2: ok
> > > 80c80
> > > < a
> > > ---
> > > > abcde
> >
> > These indicate that read with a timeout through a pipe or from /dev/tty is
> > failing (or very slow) for some reason. It's strange, since the data is
> > already written to the pipe and waiting to be read when the `read' builtin
> > is called. The /dev/tty tests can be fooled by typeahead while the tests
> > are running, but that doesn't usually happen.
>
> Could a timeout also mean that part of the data "got lost" and it's
> trying to read more than is available?

No, it reads what it can and returns it. For instance, this should return
`abcde':

read -t .0001 a <<<abcde
echo $a

since there's no reason a reasonable system should fail to read five bytes
from a pipe -- bytes that are already written, with no additional processes
involved -- in a tenth of a millisecond. I've never seen it fail, even on a
heavily loaded system.


--
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    chet@case.edu    http://tiswww.cwru.edu/~chet/