flex symbols being exported

flex symbols being exported

[Diego E. 'Flameeyes' Pettenò]

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Hello,

I'm a Gentoo Linux developer, and since last year I'm working on rooting
away problems with linking collision between software. In particular,
right now I'm working toward reducing issues with exported flex/yacc
symbols for parsers [1].

Zsh seems to be exporting quite a bit of symbols; while most of the
interface is used by the plugins, there seems to be also the parser's
symbols being exported:

yamato ~ # nm -D /bin/zsh | grep yy
08088310 T yylex
080e05f0 B yytext

I guess this comes from flex, at any rate the yylex symbol is widely
defined (50 times on my tinderbox results) and it should probably not be
avoided.

You should either hide the symbols (either via proper ELF visibility or
through linker scripts) or rename them asking for a prefixed version of
them.

HTH,

[1]
http://blog.flameeyes.eu/2008/02/09/flex-and-linking-conflicts-or-a-possible-reason-why-php-and-recode-are-so-crashy

-- 
Diego "Flameeyes" Pettenò
http://blog.flameeyes.eu/


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Re: flex symbols being exported

[Peter Stephenson]

On Thu, 19 Feb 2009 22:40:02 +0100
"Diego E. 'Flameeyes'" Pettenò <flameeyes@gmail.com> wrote:
> Zsh seems to be exporting quite a bit of symbols; while most of the
> interface is used by the plugins, there seems to be also the parser's
> symbols being exported:
> 
> yamato ~ # nm -D /bin/zsh | grep yy
> 08088310 T yylex
> 080e05f0 B yytext

These are actually internal symbols---there's no particular intention to
export them, but as the shell gets linked against its own dependent libraries
they're visible by default on many systems.

I'll commit a patch to remain them to zshlex and zshlextext.

-- 
Peter Stephenson <pws@csr.com>                  Software Engineer
CSR PLC, Churchill House, Cambridge Business Park, Cowley Road
Cambridge, CB4 0WZ, UK                          Tel: +44 (0)1223 692070