Subject Re: udf won't do what it should
Author martinknappe
Hi Adam,
I still haven't found the problem.
If you don't have the TNT controls installed, here goes a version of
the dll w/o them:

true, the sample app still uses tnt but the dll works fine with it,
trust me, so the problem is why does the exact same function not to
under firebird what it does in my sample app?
alternatively, the tnt controls can be found at

Thanx for any help,


--- In, "Adam" <s3057043@...> wrote:
> --- In, "martinknappe" <martin@>
> wrote:
> >
> > hello
> > i'm posting this in this forum because in the delphi forum no one was
> > able to help me out:
> > i've written a udf with delphi for my interbase database and i think
> > i've very much followed all the necessary instructions for doing so
> > (according to the tutorial under
> >;PAGES;NAME='ibp_howto2'
> >
> > When testing the dll with my own sample application it does exactly
> > what it's supposed to do (namely, replace a sequence of characters in
> > a widestring by a different sequence of characters)
> > You can find the dll project and the one for the sample app under:
> >
> >
> >
> > now, the problem comes in when i want to use the function in my
> > firebird database. i declared the udf via:
> >
> > CSTRING(100),
> > CSTRING(100),
> > CSTRING(100)
> > ENTRY_POINT 'Replace' MODULE_NAME 'MyFirebirdUDFs'
> >
> > And then, in order to test it, I do the following:
> >
> > select replacesubstring('Mafter', 'af', 'us') from rdb$database
> >
> > This should evidently give me 'Muster' as a result. But instead what I
> > get is 'Mafter' again. What am I doing wrong here?
> >
> Martin,
> This is not something Firebird will be doing. I do not have TNT
> components installed, so it is a little tricky for me to look at your
> pas. Nothing stands out too much to me (except the possibility of
> returning nil which I have no idea how it will handle.)
> Lucky for you it is a simple procedure. Put a few showmessage calls in
> and it should quickly become apparent if there is any issues with the
> delphi part.
> Have you confirmed that you are using the right dll (restart the FB
> Service for good measure). A showmessage will also allow you to be
> confident of this.
> Adam