Hi all,

I have a Delphi database application that is currently running on FB 2.5 
server. Application was working OK for several years on previous FB versions. I 
switched to FB 2.5 early when it was released.

This year I noticed a couple of cases when there was INF value written in 
double precision field in database. I also noticed, that Delphi Try / Except / 
End  block was not catching EZeroDivide etc. exceptions ... this is big 
problem. 
Imagine case like this:

var
  A,B,C: Real;

try
  C := A / B;  // B is zero here
except
  C := 0;
end

Exception is not raised on C calculation and C is calculated as INF.
Well I can change that and check if B is zero and do workaround, but there is 
Delphi VCL that depends on exception being raised!
That is why Delphi sets FPU Control Word to $1332 to raise exceptions.
You can read more about that here:
http://qc.embarcadero.com/wc/qcmain.aspx?d=5928

So, when I was looking for DLL that my application loads that disables FPU 
exceptions I realised that it is Firebird Client library or its MSVC RTL.

What I found out is that my delphi application is catching exceptions if I use 
FB client from version 1.5 up to version 2.1.4, but not with FB 2.5 client.

Now I wonder if it is FB Client that is builded with disabled FPU exceptions 
catching or is it MSVC RTL. I dont know if MSVC RTL changed from FB 2.1.4 to FB 
2.5 or it is the same.

If I set FPU CW to $1332 manualy in my application it works only for a couple 
of lines of code than it is back disabled again, so this is not a solution. 
Currently I am using 2.1.4 client to be on the safe side.

Does anybody knows what changed in FB 2.5 and what can be done about it?


Thank you and best regards,

Simon

Reply via email to