[vtkusers] vtkDelete in java gc finalization

[Bernard Giroux]

Le 06-09-27 à 09:32, TARRAGO Xavier 103783 a écrit :

>   Hello,
>   I use vtk from java bindings and I am very surprised about the  
> way garbaging is handled. vtkDelete is called from finalize. But  
> finalize is runned in a thread that is not the main thread (or  
> eventThread for swing). So I expected some synchronization in the  
> reference counting. But I cannot find any clue of that. Please let  
> me know that I have missed something. If I did not, I expect some  
> ref counting corruption to happend from java finalization.
>
>   Best regards,
>

This might explain the crash I describe in a previous mail (see  
below).  I ended up copying the cell point values in a java array  
instead of using the vtk object to avoid the crash.



--- previous mail here ---
I am sort of newbie at this and would like any advice...  I am  
developing on a dual G5 running Tiger.

I have a class with a private vtkPolyData member (facets), which I  
initialize in a method the following way:

public void setFacets(vtkPolyData f) {
	if (facets == null)
		facets = new vtkPolyData();
	facets.DeepCopy(f);
	facets.Update();

	...
}

I use it later on in another method:

public double gz(double[] po) {
	if (facets == null) {
		throw new NullPointerException();
	}
	double gz = 0.0;
	vtkPoints vtkPts = new vtkPoints();
	System.out.printf("Number of cells: %d\n", facets.GetNumberOfCells());
	for (int i = 0; i < facets.GetNumberOfCells(); ++i) {
		System.out.print(i + " " + facets.GetNumberOfCells());
		int nEdges = facets.GetCell(i).GetNumberOfEdges();
		System.out.print(" . 1a");
		vtkPts.DeepCopy(facets.GetCell(i).GetPoints());
		...
}

At some point in the above loop, the program crashes at the  
GetNumberOfEdges() call, with the following message.

EXC_BAD_ACCESS (0x0001)
KERN_PROTECTION_FAILURE (0x0002) at 0x00000000

Thread 12 Crashed:
0    Java_vtk_vtkTriangle_GetNumberOfEdges_15 + 68



*** This does not happen if I run the program on just one CPU ***    
Any idea???


>
> Xavier Tarrago
> Service Système et Simulation pour la Surveillance et le Contrôle  
> Non Destructif
> CEA Saclay
> 91191 Gif sur Yvette Cedex
> Tel :+ 33 (0)169 088 808
> Fax:+ 33 (0)169 087 597
> http://www-civa.cea.fr
> xavier.tarrago at cea.fr
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---
Bernard Giroux, ing., Ph.D.
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