On Mon, Jan 22, 2018 at 4:26 AM, Konstantin Belousov <kostik...@gmail.com> wrote: > On Mon, Jan 22, 2018 at 02:44:41AM +0000, Kyle Evans wrote: >> Author: kevans >> Date: Mon Jan 22 02:44:41 2018 >> New Revision: 328240 >> URL: https://svnweb.freebsd.org/changeset/base/328240 >> >> Log: >> Add libregex, connect it to the build >> >> libregex is a regex(3) implementation intended to feature GNU extensions >> and >> any other non-POSIX compliant extensions that are deemed worthy. >> >> These extensions are separated out into a separate library for the sake of >> not cluttering up libc further with them as well as not deteriorating the >> speed (or lack thereof) of the libc implementation. >> >> libregex is implemented as a build of the libc implementation with LIBREGEX >> defined to distinguish this from a libc build. The reasons for >> implementation like this are two-fold: >> >> 1.) Maintenance- This reduces the overhead induced by adding yet another >> regex implementation to base. >> >> 2.) Ease of use- Flipping on GNU extensions will be as simple as linking >> against libregex, and POSIX-compliant compilations can be guaranteed with a >> REG_POSIX cflag that should be ignored by libc/regex and disables >> extensions >> in libregex. It is also easier to keep REG_POSIX sane and POSIX pure when >> implemented in this fashion. > You are doing very fragile and unmaintainable trick on all consumers > there. Your libregex.so exports the same symbols under the same version > as the libc does. In other words, we now provide two binary-incompatible > callable symbols, and selection of the symbol by the consumer depends on > the DT_NEEDED order and interposing. For instance, if some program loads > a module linked to your libregex, the program behaviour suddenly changes. > > Since the library provides incompatible implementation, it must use > different versions for the symbols, at least to save others time to > debug the mess.
What's the best way that you see, going forward? I'm inclined to throw a Symbol.map into libregex using FBSD_1.1... these interfaces are otherwise stable stable within the two respective libraries, so I don't see that causing too much pain in the future because symbol version changes should be rare. On the other hand, I could see wanting to use something more like FBSD_LIBREGEX_1.0 so that if the situation does come up one doesn't need to double-check that they're not colliding with the other implementation. _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
