[tex-live] Re: [tex-implementors] Re: bug in etex

[Hans Hagen]

Peter Breitenlohner wrote:

> On Tue, 13 Jul 2004, Taco Hoekwater wrote:
>
>> I've been working on this for quite a few hours now, and there really 
>> is a bug
>> somewhere in the (web2c version of) the etex code. The following 
>> extended
>> mode plain input file causes both of pdfetex and etex (Web2c 7.5.3 
>> and 7.4.5)
>> to quit with SIGSEGV under linux:
>>
>> ------
>>  \toksdef\whatevertoks = 266
>>  \toksdef\extratoks = 267
>>  \whatevertoks={junk}
>>  \everypar{\extratoks=\whatevertoks}
>>  \immediate\write16{t={\the\toks265}}
>>  some paragraph\par
>>  \bye
>> -------
>>
>> It seems that the '\the' command that accesses a previously undefined 
>> token
>> register is what is causing the problem later on; the SIGSEGV happens 
>> when
>> TeX tries to access the RHS of the \extratoks=\whatevertoks assignment.
>
>
> Hi Taco,
>
> I have just reproduced the SIGSEGV with
>     "This is e-TeX, Version 3.14159-2.1 (Web2C 7.3.1)"
> (yes we still use this somewhat oldish version).
> I'll have to look into the code to find out what goes wrong.
>
> --------------------------
>
> Could any one test this on a non-linux Unix system and report the 
> outcome?

In the process of uncovering the bug taco worked on unix and i tested on windows; both old and new versions of pdfetex show the problem 

in some cases there is no segfault but registers end up empty (null pointer of so) 

Hans 

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