[vtk-developers] asymmetry of SetNumberOfComponents and SetNumberOfTuples

[Goodwin Lawlor]

While we're on this subject of array allocation... Either

vtkPoints p
  p GetPoint 0

Or 

vtkFloatArray fa
  fa GetTuple1 0

Etc.

Both crash if they aren't allocated. There's no check to see if the id
exists. Should there be? Or should an application check explicitly?

Goodwin
University College Dublin

-----Original Message-----
From: vtk-developers-admin at vtk.org [mailto:vtk-developers-admin at vtk.org]
On Behalf Of Michael Halle
Sent: 22 April 2004 17:46
To: 'VTK Developers'
Subject: [vtk-developers] asymmetry of SetNumberOfComponents and
SetNumberOfTuples


Today I got burned by the fact that if you have
a data array and you call

SetNumberOfComponents, then
SetNumberOfTuples

everything is fine, but

SetNumberOfTuples, then
SetNumberOfComponents

will cause a core dump for ntuples > 1.

Turns out that SetNumberOfTuples does the allocation,
while NumberOfComponents is just an ivar.

This seems like it would be a pretty common "gotcha":
shouldn't both allocate or reallocate as needed?

(Yes, this behavior is sort of documented, but that's not
the point.)

Michael Halle
mhalle at bwh.harvard.edu

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