Invalid Pointer

rbuser

Our RBServer has been running as a Window2003 service for several weeks
error free (the few times it failed we knew why). Today one of the reports
created a 'EInvalid Pointer, Invalid pointer operation' and stopped
RBServer. I tired duplicating the error on a development server and a
mirror of the db, but the report runs fine in the development/test
environment. Any ideas where to begin looking or what might cause this
error? Delphi2006, RB10.04, Oracle, ADO Connection, Form based reports.
Thanks for the help.

nardmoseley

Make sure that the report form is thread-safe. Do not use any unit level
'vars' or global objects. Use only instance variables.

When testing in the development sever, try some tests in which two clients
request the same report.



--
Nard Moseley
Digital Metaphors
www.digital-metaphors.com

nardmoseley

RB Server is multi-threaded and will create a separate instance for each
report that generates. The report must have a thread safe environment in
which to execute.


Avoid using global/unit level variables/objects in a server environment -
because they are not thread-safe.




Here are simple definitions...



- a local variable is a variable declared inside a method
- a parameter is variable that is passed to a method

Example:



procedure TForm1.myFunction(aParameter: Integer);

var

lsLocalVariable: String;
begin

end;





- an instance variable is variable declared as part of a class. Instance
variables can be private, protected, or public.



Type

TForm1 = class(TForm)
private

FPrivateVariable: String;

Public

FPublicVariable: string;
end;




- a unit level variable (also called a global variable) is a variable that
is not part of a class instance. These variables can be declared in the
interface or implementation section and are /not/ thread safe.

interface


var

myGlobalVar: string;

implementation



var

myUnitVar: string;





--
Nard Moseley
Digital Metaphors
www.digital-metaphors.com

rbuser

> Our RBServer has been running as a Window2003 service for several weeks

We have seen this problem caused by RBServer leaving thousands of temporary
files in c:\windows\temp. Delete those files and the problem goes away.

Terry.