In one of my sistem I use the Substr UDF. In the app folder I create a
folder name "firebird" and put all the files needed to run the
embedded version of firebird. The problem is that the UDF substr
function doesn't work, I obtain the error that is not defined, but if
in the connection string I use the c:\windows\system\gds32.dll the UDF
substr function work fine!!!!!.

Inside the folder "firebird" create in the folder of the app exist the
UDF folder with all the files inside.

I dont understand why if I use the gds32.dll in diferent location the
UDF function work fine.

The firebird version is 2.0

Best Regards
Diego Gandino