Re: building GNU gettext on AIX

[Bruno Haible]

David Edelsohn wrote:
> > It is great that gettext and libintl can be built thread-safe, but GCC
> > (cc1, gcov, etc.) are not pthreads applications and are not built with
> > pthreads.  Because libintl defaults to pthreads enabled, NLS cannot
> > function in GCC on AIX by default.  
> ...
> The latest issue is that a few files in gettext ignore --disable-pthreads
> and creates a dependency on pthread_mutex.

GNU gettext does not have an option '--disable-pthreads'. Instead, it has
options

  --enable-threads={isoc|posix|isoc+posix|windows}
                          specify multithreading API

  --disable-threads       build without multithread safety

> The issue appears to be that intl/gnulib-lib/{mbrtowc.c,setlocale_null.c}
> include pthread.h based on HAVE_PTHREAD_API, which is defined as 1 in
> intl/config.h build directory

Yup, I confirm that the dependency comes from these two object files.

Will the next GCC release support AIX 7.1.x ? Recall that AIX 7.1 went
end-of-life on 2023-04-30 [1]

  * If no, then the simple solution would be to pass the configure option
      --enable-threads=isoc
    This should not introduce a link dependency, because the mtx_lock,
    mtx_unlock, and mtx_init functions are in libc in AIX ≥ 7.2. Currently it
    does not work (it still uses pthread_mutex_lock and pthread_mutex_unlock
    despite --enable-threads=isoc). But I could make this work and release
    a gettext 0.22.4 with the fix.

  * If yes, then the question is how distributors will in general package
    libintl on AIX. If it's installed in public locations (such as in
    /opt/freeware/{lib,lib64}/libintl.a on gcc119.fsffrance.org), then we
    have a problem: It may cause undefined behaviour in multithreaded
    packages that use GNU libintl.
    If you can guarantee that it will be installed in GCC-private directories
    (and outside the path where GCC looks for libraries to link with!) then
    it would be OK to install such a non-thread-safe libintl.
    But if you cannot guarantee that, we are in trouble.

    How do other library vendors handle this issue on AIX? Do they ship two
    libraries, one MT-safe and one not? Under different names? Or in different
    library search paths?

Bruno

[1] https://www.ibm.com/support/pages/aix-support-lifecycle-information