Hi Martijn,

> I just found out that by default, the new IBO will load
> fbclient.dll (if it can find it) over gds32.dll (the old
> behaviour).

I think this one is probably my fault, being part of some
changes that I sent to Jason to allow changing of the client
library at runtime. There are really two parts to this.


1. The decision to use a function ptr global instead of having
users change the old library constant/variable.

The IB_GetClentLibName function ptr variable should be used
in preference to changing the library name "constants".

To use it...

program
MyProgram;
uses
Forms,
IB_Session, // Must use IB_Session
// etc
;

function GetFBClientLibName: string;
begin
Result := 'myfbclient.dll';
end;

begin
// Tell IB_Session where to get the client lib name
IB_GetClientLibNameFunc := GetFBClientLibName;
// then continue with the normal stuff
Application.Initialize;
// etc
end.

Why is this better than changing the "constant"? Because it
becomes possible to have the client library dynamically load
and unload as needed - and so also provides the potential to
write programs that switch between using different libraries
(one at a time). Without having to time when to change the
"constant" variable.

In the future Jason may also find ways of allowing different
session instances to use different libraries. A function
is better placed to support such functionality (although
whether its signature may need to change to take a parameter
or two is unclear at the moment).


2. The choice of which "default" client library name to try
first when no specific client library has been specified.

The choice to do one or the other first is pretty arbitrary
really. I chose Firebird because thats what I use and I
find it hard to imagine ever wanting Interbase - so I save
a couple of clock cycles by doing it first, and save having
to create gds32.dll in a Firebird installation.

Which ever is chosen as the arbitrary first/default library
name, you are already in a precarious situation if you have
incompatible versions of both fbclient.dll and gds32.dll
available in your path.

> This can cause weird errors, like in my situation, after
> the IBO upgrade, my application tried complaining about a
> wrong ODS version because it was connecting to Firebird
> instead of InterBase.

How is this any different to the reverse situation that seems
just as likely? How is attempting gds32.dll first going to
help or make anything more reliable?

Short of holding a poll to indicate numbers of IB vs FB users
it is impossible to tell if there should be any overall
preference (ideally the most commonly used should be the
first one tried). If Jason wants to reverse the order then
that is fine with me, but it seems to me that your problems
are symptomatic of larger installation issues.

--
Geoff Worboys
Telesis Computing