Martin

>> 1) Did you stop and restart the server before trying to use the new
>> library ? The error message you got seems to indicate that you
> didn't....
>
> Yes I did.
>
>> 2) You don't need the custom entry in firebird.conf if your UDF
>> library is in the default directory.
>
> Just to make sure I tried it out but true, I read somewhere else as
> well that the standard directory needs not be explicitly mentioned.
>
>> 4) Didn't look at your code, but what calling convention do you use
>> to export your function? It needs to be cdecl, not stdcall.
>
> What's the difference? Would you please have a look at my code and
> tell me whether I got the coding right?
>

You don't export your function, so the dll has no idea what it has to do with that call

Modify your dll code like this:

uses
SysUtils,
Classes,
Strings in 'Strings.pas';

{$R *.res}
exports
REPL resident;

begin
end.

I changed the name of the function to REPL instead of Replace.

Florian