Comment 1 for bug 107209

Another response, clarifying the issue. I was incorrect about the mail-list archive: it's on zsh-workers, not -users:
http://www.zsh.org/mla/workers/2007/msg00200.html

> Works as I'd expect from your man page quote here:
>
> $ time zsh -c 'ulimit -t 0; while :; do :; done'
> zsh: cpu limit exceeded zsh -c 'ulimit -t 0; while :; do :; done'
> zsh -c 'ulimit -t 0; while :; do :; done' 0.72s user 0.28s system 95% cpu 1.050 total
> $ time bash -c 'ulimit -t 0; while :; do :; done'
> zsh: killed bash -c 'ulimit -t 0; while :; do :; done'
> bash -c 'ulimit -t 0; while :; do :; done' 1.00s user 0.00s system 95% cpu 1.047 total
> $ uname -a
> Linux sc.homeunix.net 2.6.21-rc4 #1 PREEMPT Sun Mar 25 15:39:31 BST 2007 i686 GNU/Linux
> ~$ uname -rs
> Linux 2.6.21-rc4

Yes, I get those same results. However, in an interactive shell:

% ulimit -t 0
% ( ulimit -t; while :; do :; done )
0
<< watch the CPU time used climb in top >>
^C
%
...
% ulimit -Ht 0
% ( ulimit -t; while :; do :; done )
0
zsh: killed (; ulimit -t; while :; do; :; done; )
%

My first thought was: is zsh blocking SIGXCPU in some circumstances? But
killing the process with kill -XCPU worked fine.

It therefore appears that while the man page is correct for hard limits,
soft limits of 0 are still treated as unlimited.