Re: [bug-gawk] Does gawk deal with signal pipe correctly?

[arnold]

What is the output from gawk --version?

Peng Yu <address@hidden> wrote:

> Here is what I have. It is tested on a virtual machine (hosted on KVM
> on another Ubuntu physical machine). Are you able to get the same
> version vm to test?
>
> $ cat DCt7x2zD | awk '{ print }' | head -n 1
>
> $ echo address@hidden
> 0 141 0
> $ cat DCt7x2zD | awk '{ print }' | head -n 1
>
> $ echo address@hidden
> 0 1 0
> $ cat /etc/issue
> Ubuntu 14.04.5 LTS \n \l
>
> $ uname -a
> Linux caph 3.13.0-144-generic #193-Ubuntu SMP Thu Mar 15 17:03:53 UTC
> 2018 x86_64 GNU/Linux
>
> I also tried on a non vm Ubuntu machine. But I don't see 0 1 0, though.
>
> On Sun, Jun 17, 2018 at 2:06 AM,  <address@hidden> wrote:
> > On a Redhat system using current code and your file I got 0 0 0 one time
> > and 0 141 0 the rest of the times I tried. It appears to be a timing
> > issue.
> >
> > The pipe(7) man page says
> >
> >         In Linux versions before 2.6.11, the capacity of a pipe was the 
> > same as
> >         the system page size (e.g., 4096 bytes on i386).  Since Linux 
> > 2.6.11,
> >         the pipe capacity is 65536 bytes.
> >
> > Your file is a little over 18000 bytes, so it fits entirely into a
> > single pipe buffer.  It looks like the 0 0 0 happens when gawk succeeds to
> > read and write the data before head runs, and SIGPIPE otherwise.
> >
> > Unless there is a way to reproduce this consistently so that I can
> > trace the code in a debugger, there's not a lot more I can do.
> >
> > Thanks,
> >
> > Arnold
> >
> > Peng Yu <address@hidden> wrote:
> >
> >> You must use the file that I provided to reproduce the problem `seq
> >> 10000000` will not reveal the problem as I have shown in my original
> >> post.
> >>
> >> I also tested on Ubuntu. Sometimes it shows 0 1 0 and sometimes it shows 0 
> >> 0 0.
> >>
> >> $ cat DCt7x2zD | awk '{ print }' | head -n 1
> >>
> >> $ echo address@hidden
> >> 0 1 0
> >> $ awk --version | head -n 1
> >> GNU Awk 4.2.0, API: 2.0 (GNU MPFR 4.0.1, GNU MP 6.1.2)
> >>
> >>
> >> On Sat, Jun 16, 2018 at 1:51 PM,  <address@hidden> wrote:
> >> > Hello.
> >> >
> >> > I don't think this is an awk issue.  In any case, I can't
> >> > reproduce the problem:
> >> >
> >> >         $ gawk --version | sed 1q
> >> >         GNU Awk 4.2.0, API: 2.0 (GNU MPFR 3.1.4, GNU MP 6.1.0)
> >> >         [tanda:pts/2 arnold]$ for i in nawk mawk gawk
> >> >         > do
> >> >         > echo === $i
> >> >         > seq 10000000 | $i '{ print }' | head -1
> >> >         > echo address@hidden
> >> >         > done
> >> >         === nawk
> >> >         1
> >> >         141 141 0
> >> >         === mawk
> >> >         1
> >> >         141 141 0
> >> >         === gawk
> >> >         1
> >> >         141 141 0
> >> >
> >> > Arnold
> >> >
> >> > Peng Yu <address@hidden> wrote:
> >> >
> >> >> Hi,
> >> >>
> >> >> $ seq 10000000 | awk -e '{ print }' | head -n 1
> >> >> 1
> >> >> $ echo "address@hidden"
> >> >> 141 141 0
> >> >> $ tmpfile=$(mktemp -u)
> >> >> $ seq 10000000 > "$tmpfile"
> >> >> $ cat "$tmpfile" | awk -e '{ print }' | head -n 1
> >> >> 1
> >> >> $ echo "address@hidden"
> >> >> 141 141 0
> >> >>
> >> >> In the following case, I see that awk sometimes return 1 instead of 0
> >> >> for the input tmp2.txt (download at
> >> >> https://pastebin.com/raw/DCt7x2zD). But I never see awk returns 141
> >> >> for this file. Is this behavior of awk correct? Should it always
> >> >> return 141?
> >> >>
> >> >> $ cat < tmp2.txt | awk -e '{ print }' | head -n 1
> >> >>
> >> >> $ echo address@hidden
> >> >> 0 1 0
> >> >>
> >> >> --
> >> >> Regards,
> >> >> Peng
> >>
> >>
> >>
> >> --
> >> Regards,
> >> Peng
>
>
>
> -- 
> Regards,
> Peng