#1 re-entrant lwes_emitter_create

Next Minor Release
open
Michael Lum
C API (1)
5
2009-04-10
2009-04-02
Anonymous
No

it would be nice lwes_emitter_create() was re-rentrant (since flex/bison is compiled non-re-entrant) or held a lock. lwes_emitter_create() should probably be only used once per thread. i'll get clarity into how important this is soon. thanks.

Discussion

  • Michael Lum
    Michael Lum
    2009-04-10

    will look into making the ESF parser re-entrant.

    pthreads is not linked by design so that LWES has a minimal dependency set (for those wanting to use it in embedded applications)

     
  • Michael Lum
    Michael Lum
    2009-04-10

    • milestone: --> Next Minor Release
    • labels: --> C API
    • assigned_to: nobody --> mlum
     
  • Michael Lum
    Michael Lum
    2009-04-22

    Some progress has been made in revisions 101 and 110, however, it is not quite complete.
    http://lwes.svn.sourceforge.net/viewvc/lwes?view=rev&revision=101
    http://lwes.svn.sourceforge.net/viewvc/lwes?view=rev&revision=110

    These changes are released in lwes-0.22.3.

    These changes change the bison parser to use the "pure parser" mode. However, there still need to be changes in order to have a reentrant flex. The most problematic part is that many systems still have flex-2.5.4 on them (RHEL5/CentOS 5 being the most common) and reentrant flex lexers were introduced after that version.

    For lwes-0.23.x, I'm suggesting the following:
    - add a configure.ac macro to detect flex version and add a --enable-reentrant configure flag that requires a newer flex that supports the %option reentrant string
    - add respective flags in config.h, and preprocessors in the .l and .y files depending on the value of the reentrant option

    Users can then choose to compile lwes using a newer flex with reentrant support, or the older flex without it.

    The latest change does allow multiple parsers to be created though.