[Fwd: [Insight-developers] TImage::ImageDimension]

[Luis Ibanez]

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Hi Yinpeng,

It looks like a similar problem that we have 
encounter previously.

This is a warning tha only happens in VC++,
and in spite of the warning, the code runs
correctly.




-------- Original Message --------
Subject: [Insight-developers] TImage::ImageDimension
Date: Fri, 27 Oct 2000 11:06:09 -0400
From: Luis Ibanez <ibanez@cs.unc.edu>
Reply-To: luis.ibanez@ieee.org
Organization: Medical Image Display and Analysis Group MIDAG-UNC
To: "insight-developers@public.kitware.com"
<insight-developers@public.kitware.com>
References:
<7F537688E0D6D0119A0B00805FFEBE9404660F3F@exc03crdge.crd.ge.com>


Hi,

Looking closer into the problem of using ImageDimension,
there are some funny facts:

1) In VC++ 6.0 this produce  a warning, not an error

2) The warning doesn't appears with gcc,  maybe
     because gcc doesn't complain about zero
    size arrays being declared  like:    int m[0];

3)  In spite of the warning,...
      the code runs ok  with gcc and VC++.

------

This is a minimal example of the similar situation.
Here, a short "Image" class is used, just to isolate
the code from the rest of Insight, so the attached
file is self-contained.

The output of the program shows that the dimension
of the image created inside the process object is
really 3 as expected.

I will speculate that this is due to the different aspects
of the code that are checked during the several compiler
passes.  Perhaps enums are initialized after array sizes
are checked....



Luis


==================================

#include <iostream>

//--------------------------------
// Image Class
//--------------------------------
template <class T, unsigned int N>
class Image {
public:
  enum { ImageDimension = N };
  typedef Image * Pointer;
private:
  unsigned int Index[N];
};


//--------------------------------
// Process Class
//--------------------------------
template <class TImage>
class myProcess {
  typedef Image<int, TImage::ImageDimension> TempImage;
  typename TempImage::Pointer temp;
public:
  myProcess() {
    std::cout << "image dimension = ";
    std::cout <<  TempImage::ImageDimension << std::endl;
  }
};

//--------------------------------
// Main
//--------------------------------
int main()
{
  typedef Image<float,3> myImageType;
  myProcess<myImageType> process;
  return 0;
}




--
______________________________________________________________________

Luis Ibanez
Research Assistant Professor - Division of Neurosurgery
University of North Carolina at Chapel Hill
CB# 7060, Chapel Hill, NC 27599
email : ibanez@cs.unc.edu       home  : http://www.cs.unc.edu/~ibanez
phone : (919)-843-9961          fax   : (919)-966-6627
______________________________________________________________________
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