data loss in pipes

data loss in pipes

[Jamax]

Hi,

I've been having some problems with pipes and data loss with zsh and I wanted to bring it to your attention.  Recently I noticed that linux kernels would not compile as they would either fail during assembly because of strange errors (comments interpreted as instructions, etc) and then it started happening in some software at work and I finally clued in that zsh is losing data through pipes.

For example, I run:
    make 2>&1 | grep 'undefined reference'

And I usually get a truncated list as a result, whereas with bash and it always prints the full output (the kernel compiles work in bash too).

My gentoo config:
    sys-devel/gcc-3.4.2-r2
    app-shells/zsh-4.2.1
    app-shells/bash-3.0-r6
    sys-kernel/development-sources-2.6.9_rc2
    CFLAGS=-O -fPIC -pipe

I think this could possibly be a gcc compiler problem, as I compiled gcc, make, etc with these cflags:
    CFLAGS=-O2 -ftracer -fprefetch-loop-arrays -march=pentium4 -frename-registers -fmove-all-movables -freduce-all-givs -pipe

Jam

Re: data loss in pipes

[Denis Lagno]

> I think this could possibly be a gcc compiler problem, as I compiled gcc,
> make, etc with these cflags:
>     CFLAGS=-O2 -ftracer -fprefetch-loop-arrays -march=pentium4
>            -frename-registers -fmove-all-movables -freduce-all-givs -pipe

I myself had problems with -frename-registers in previous versions of gcc.
And manpage of gcc-current explicitly states that -frename-registers has
known bugs.
--
Denis Lagno,
PGP key fingerprint: F94F F38F 1895 E673 4374 9D63 2B9E FAB3 8E83 584C