On Fri, 2008-08-01 at 09:46 +0200, Markus Hoenicka wrote:
> Quoting Balazs Scheidler <[EMAIL PROTECTED]>:
>
> >
> > Hi,
> >
> > I was trying to compile libdbi on AIX 5.2, which lacks RTLD_NEXT used by
> > libdbi to resolve something called "custom functions".
> >
> > I've grepped the libdbi-drivers code, and none of the drivers currently
> > use custom_functions.
> >
>
> The custom_function interface has been around since the days of yore
> (i.e. before I joined the project) without a proper documentation. I
> assume it was originally intended to allow drivers to export
> additional functions which extend the libdbi API for that particular
> driver. No driver has used the interface this way yet. However we
> received a request lately to support some PostgreSQL client library
> functions which are not covered by the libdbi API. This led to the
> idea to export all client library functions through the
> custom_function interface to make them available to libdbi end-users
> (who should know what they're doing as this leads to driver-specific
> code in their programs). This is also why no driver accesses this
> interface, but many drivers export functions via this interface (at
> least in cvs).
>
> > I was wondering what the aim with this function is, and whether I could
> > replace RTLD_NEXT with the driver's shared object handle. E.g. something
> > like this:
> >
> > [EMAIL PROTECTED]:~/src/libdbi8-0.8.3/src$ diff -u dbi_main.c
> > dbi_main.c-bazsi
> > --- dbi_main.c 2008-06-02 14:45:33.000000000 +0200
> > +++ dbi_main.c-bazsi 2008-08-01 08:57:46.000000000 +0200
> > @@ -1277,7 +1277,7 @@
> > /* snprintf(function_name, 256, DLSYM_PREFIX
> > "dbd_%s", custom->name); */
> > /* printf("loading %s<<\n", custom->name); */
> >
> > - custom->function_pointer = my_dlsym(RTLD_NEXT,
> > custom->name);
> > + custom->function_pointer = my_dlsym(driver->dlhandle,
> > custom->name);
> > if (!custom->function_pointer) {
> > /* printf(my_dlerror()); */
> > /* this usually fails because a function was
> >
> >
>
> Please have a look at the latest cvs revisions of dbi_main.c and the
> related autotools files (configure.in, Makefile.am etc.). The dlsym
> stuff is platform-dependent, and I've started to implement a mechanism
> which autodetects the proper value of the handle. If AIX requires
> dlhandle, it is a matter of setting DLSYM_HANDLE appropriately in
> configure.in for this platform. I'd greatly appreciate if you could
> test the current cvs revision of libdbi on AIX and report whether the
> tests in place work appropriately for that platform.
If these functions are indeed exported by the driver module, I don't see
why you are using RTLD_NEXT at all. You could simply resolve the symbol
from the shared object itself. Or am I missing something?
We need to test the functionality on AIX, so we will. I drop you an
email once we did that.
--
Bazsi
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