Re: Question about POSIX regex support

[Gallagher James]

On Jun 21, 2007, at 6:07 PM, Bruno Haible wrote:


> Hello,
>
> Gallagher James wrote:
>
> > System specifics: Fedora Core 6, intel, gcc/++ 4.1.1.
>
> And what's the CPU? x86 or x86_64? 32-bit or 64-bit?

x86_64.


> > Problem 1: With a string "123abcdef" and a regex of "abc", after
> > calling regex(...) the resulting pmatch[] has values very different
> > than before. In the past the result of this call was that pmatch
> > [0].rm_so was 3 and pmatch[0].rm_eo was 6. Now I get pmatch[0].rm_so
> > = 3, pmatch[0].rm_eo = 0, pmatch[1].rm_so = 6 and pmatch[1].rm_eo =
> > 0. It seems that the new result is not correct.
> >
> > Problem 2: Using valgrind I'm getting an Invalid write of 8 bytes on
> > lines 950 and 951 of regexec.c.
>
> Both symptoms hint towards mismatching definitions of 'regoff_t'.  
> Namely,
> it looks like the regoff_t that your program is using/seeing is 32-bit
> wide, whereas the regoff_t that gnulib's regex module is using is  
> 64-bit
> wide.

Yup, that was it.

> Here's a checklist:
>
>   1) Verify the values of sizeof (regoff_t) in three different  
> configurations:
>      - with the system header (-I/usr/include)
32

>      - with the gnulib regex.h and with config.h (-Ilib - 
> DHAVE_CONFIG_H)
64

>      - with the gnulib regex.h and without config.h (-Ilib)
32

>      Test program:
>
>            #if HAVE_CONFIG_H
>            # include <config.h>
>            #endif
>            #include <stdio.h>
>            #include <regex.h>
>            int main () { printf ("%d\n", 8 * sizeof (regoff_t));  
> return 0; }
>
>   2) Verify that you have the -I option in place so that your  
> program uses
>      the regex.h from gnulib, not the one from /usr/include.
>
>   3) Verify that every source file that includes gnulib headers  
> starts out
>      with   #include <config.h>.

Problem fixed.

Thanks very much!

James

> Bruno

--
James Gallagher                jgallagher at opendap.org
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