[fpc-pascal] what is the possible cause of EPrivilege Privileged instruction ?

Tony Whyman tony.whyman at mccallumwhyman.com
Wed Oct 26 18:12:55 CEST 2016

A couple of ideas (no more than this)

1. A corrupt stack has resulted in a function return address being 
corrupted and the program jumps to an illegal instruction.

2. Executing data (shouldn't really happen).

3. Corrupt VMT sgain resulting in the program jumping to an illegal 

The problem with these type of bugs is that cause and effect can be some 
way apart. I tend to debug multi-threaded programs that are mis-behaving 
by having lots of writeln statements and then looking at the output log 
to see which patterns of behaviour lead to the problem. Can be an art 
rather than a science.

On 26/10/16 16:57, Dennis wrote:
> I have a multi threaded program which executes a list of tasks in real 
> time.
> It is difficult to debug with a debugger on this program (since 
> debugging will pause the execution which will be messy for this 
> application).
> So, I log the exceptions to a log file and I found this exception:
> EPrivilege    Privileged instruction
> What could possibly raise this exception?
> My program is win 32 from Lazarus 1.7  FPC 3.1.1
> and running on Win 7 64 bit.
> thanks in advance.
> Dennis
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