[Lazarus] animated splash screen for lengthy operation, works with windows, doesn't with linux

Luca Olivetti luca at wetron.es
Mon Mar 27 17:26:01 CEST 2023

El 27/3/23 a les 16:50, Michael Van Canneyt ha escrit:

>>> Ehm. In case of an exception, ut will never be freed ?
>> That's what I said.
>> I was looking for a way to free it *and* raise the exception in the 
>> context of the main thread.
>> If I move the ut.free before the raise, the exception has already been 
>> freed and it's invalid, causing a sigsev, if I enclose it in a 
>> try..finally the exception handler will be called after the finally 
>> has freed the thread (and the exception, so it's the same problem).
> Normally, I'd do
> Raise 
> Exception(ut.fatalexception.classtype).Create(ut.fatalexception.message);

Actually I'd have to first create the exception, then free ut, then 
raise the exception (keep in mind that FatalException is a TObject and 
it isn't necessarily of class Exception), otherwise a direct raise as 
you wrote would not free ut.

   if ut.FatalException<>nil then
      if ut.FatalException is Exception then
   if MyException<>nil then
     raise MyException;

But it still doesn't work, since this way MyException is a copy of 
FatalException (i.e. it's no different than 
MyException:=Exception(ut.FatalExcaption), so freeing ut, which in turn 
frees ut.FatalException, makes it invalid and causes a sigsev.

The best I could do is store the exception message and raise a new one.

Luca Olivetti
Wetron Automation Technology http://www.wetron.es/
Tel. +34 93 5883004 (Ext.3010)  Fax +34 93 5883007

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