[Developers] multi-threaded derivative stuff

[dave fournier]

On 12-07-22 10:49 AM, dave fournier wrote:

I don't quite understand it but there was some kind of conflict between the
destructor and the code called in at_exit to clean up stuff including 
open files.
Making sure the gradient_structure destructor gets called first seems to 
fix the problem.

Also the safe_mem versions of  mem_malloc and mem_free used in the 
string class are not
thread safe. they should be replaced with malloc and free.  this all 
happens in
string1.cpp  which is attached.





> Hi All,
>
> I recall that at the developers conference over a year ago there was a 
> lot of
> interest in multi-threading so long as no one actually had to produce 
> anything.
> It appeared that global variables might be a problem.    I thought it 
> might be
> of value to produce a proof of concept example with multi-threading for
> dvariable types.  The  code runs without any reported errors
> (by valgrind) so I think I am getting close.   There are also some 
> strange mysteries.
>
> If I write the code as
>
>     master()
>     {
>         // stuff
>         gradient_structure gs(10000)
>         // stuff
>
>
>    }
>
>      slave()
>     {
>         // stuff
>         gradient_structure gs(10000)
>         // stuff
>
>    }
>
> There are some obvious problems when the destructor for gs gets called.
> But if I write the code as
>
> master()
>     {
>         // stuff
>         gradient_structure * pgs = new gradient_structure(10000)
>         // stuff
>         delete pgs;
>          pgs=0;
>
>    }
>
>      slave()
>     {
>         // stuff
>         gradient_structure * pgs = new gradient_structure(10000)
>         // stuff
>         delete pgs;
>          pgs=0;
>    }
>
> all is OK.  So obviously there is something I don't understand or 
> still an error in the code.
> If anyone is interested I am happy to share the code and the problem. 
> I'll hold my
> breath.
>
>          Dave
>
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