Regex library

[Pietro Paolini]

Hi all,

I apologize if this email highlight some misunderstanding of the sed
internals from my end - I am not proficient in the build system its uses
therefore it is not extremely easy for me to dig out info from there.

In the sed source code there is a folder called lib/ which seems to include
the GNU lib and or maybe I am flay wrong and that isn't gnulib

Another question concerns the regex library in use, I can see the code
using regex functions defined as part of gnulib


https://www.gnu.org/software/gnulib/manual/html_node/GNU-Regex-Functions.html#GNU-Regex-Functions

Yet when I ldd the sed binary I can observe that PCRE is dynamically linked

~/local/src/sed-4.8 $ ldd `which sed`
        linux-vdso.so.1 (0x00007ffe785df000)
        libselinux.so.1 => /lib/x86_64-linux-gnu/libselinux.so.1
(0x00007eff9bd62000)
        libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007eff9bb70000)
        libpcre2-8.so.0 => /lib/x86_64-linux-gnu/libpcre2-8.so.0
(0x00007eff9bae0000)
        libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007eff9bada000)
        /lib64/ld-linux-x86-64.so.2 (0x00007eff9bde2000)
        libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0
(0x00007eff9bab7000)

What library is used for regex in GNU sed ? I inclined to say that PCRE
isn't used, after all libpthread gets linked too and it is not used.

Would someone be able to case some light on the matter ?

Thanks,
Pietro.