FreeTDS Development Group

["Coleman, Dave" <DColeman AT US.TIAuto.com>]

It's a day late, but if you're still looking for suggestions to help with
the ICONV mis-match, I think this might work.  What does anyone else think?

Set up the ICONV stuff be a small structure pointer in TDSSOCKET.  

Something like:

struct tds_iconv_info
{
        int use_iconv;
        iconv_t cdto;
        iconv_t cdfrom;
}       TDSICONVINFO;

then TDSSOCKET would look something like this

...
        TDSICONVINFO *tds_iconv;
        char *date_fmt;
        TDSCONTEXT *tds_ctx;
} TDSSOCKET;

modify tds_alloc_socket(...)

371:            tds_socket->parent = (char*)NULL;
        +       tds_socket->tds_iconv = (char*)NULL;
372:            tds_socket->env = tds_alloc_env(tds_socket);

add a few functions:

TDSICONVINFO* tds_alloc_iconv(TDSSOCKET *tds);
void tds_free_iconv(TDSSOCKET *tds);
and
TDSICONVINFO* tds_geticonv(TDSSOCKET *tds)
        {
        /*
        1) do some environment stuff to find if can use iconv on the
system...
                might be sloppy, but keeps ICONV out of TDSSOCKET.
                Someone with a better knowledge of configuration stuff than
                myself may know a good way to get this information out
                of the system at run time.
        */
        if( /* has iconv stuff */)
                {
                tds->tds_iconv = tds_alloc_iconv(tds);
                }
        /*
        do what ever else you need to do to set things up
        */
        return tds->tds_iconv;
        }

add a call to tds_free_iconv(...) from tds_free_socket(...) and you should
be done unless I've missed something dumb.

It doesn't solve the root problem of needing to determine if a system has
ICONV support at run-time, but it does allow the TDSSOCKET structure (and
the library) to be independent of ICONV.  It could simplify the functions
dealing with it as well.  The prototpe would not change at all, they would
still get a TDSSOCKET.  Compile the library with the tds_iconv[xxx](...)
functions if the headers exist on the system, and the functions can test for
if ( tds_socket->tds_iconv ) and as long as tds_alloc_socket(...) sets the
tds_iconv pointer to NULL, any tds_iconvblah(...) function can fail safely
if no support is present, or it has not been initialized.  This could
prevent people from trying to use the features if they had not been compiled
into the library without including config.h.  The library would compile but
the application would not if it tried to link in the ICONV functions on a
system with an ICONV-less OS or freeTDS distribution.  It's still a link
error and not completely clean, but that's a heck of a lot better than a
seg-fault.

Thoughts, comments?

Dave

> -----Original Message-----
> From: Brian Bruns [SMTP:camber AT ais.org]
> Sent: Monday, August 12, 2002 10:37 AM
> To:   TDS Development Group
> Subject:      [freetds] Re: Crash in tsql
> 
> Actually, this fix is bad, since we don't distribute config.h (nor should
> we) things won't build.  If we don't do it in the header file however, we
> are in trouble of having mismatched structure definitions.  We didn't
> really notice it before because iconv_t cdto, cdfrom was the last entry.
> 
> We simply can't be checking HAVE_ICONV in tds.h (or any distributable
> header).  We could substitute from configure but that strikes me as
> sloppy.  Any other options?
> 
> Brian
> 
> > Ok, I was on the right track, sizeof(*tds) differed between the two, I 
> > just didn't have time to finish it off.  config.h should be included
> from
> > tds.h (tds.h.in) otherwise we'll have this problem again in the future.
> > 
> > Checking the fix in now.
> > 
> > Brian
> > 
> > On Sun, 11 Aug 2002 freddyz77 AT tin.it wrote:
> > 
> > > > This has been the topic of discussion for the past couple of days.
> For
> > > > some reason tds->tds_ctx is NULL after the call to tds_connect(),
> although
> > > > it is set within tds_connect().  I haven't had a chance to track it
> any
> > > > further.
> > > > 
> > > > Brian
> > > > 
> > > 
> > > Ok, after a bit debug (assembly level at the end) I found the problem.
> > > You do not include config.h in tsql, so tds_socket appear to tsql
> without
> > > iconv stuff.
> > > 
> > > Add "#include <config.h>" on top of tsql.c and it run correctly.
> > > Perhaps is best to include config.h from tds.h.in ...
> > > 
> > > freddy77
> > >
> 
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