CODEWITHSUNDEEP
c++gccclang
Kasper Marstal
Kasper Marstal

Reputation: 352

#ifdef in separate header not working as expected

I have a #define in a separate header file:

#ifndef __sitkConfigure_h
#define __sitkConfigure_h

#define SITK_4D_IMAGES

#endif // __sitkConfigure_h

(full source: https://github.com/kaspermarstal/SimpleITK/blob/8be437486dce85da271576f866393cd54fe0f865/Code/Common/src/sitkConfigure.h.in. The define is managed by a #cmakedefine and turns into #define SITK_4D_IMAGES as expected when cmake is configured.)

As usual the header is included where the config is needed. For example:

#include "sitkConfigure.h"

#ifdef SITK_4D_IMAGES
/** \brief Constructor for 4D images where pixel type can be specified.
 * @{
 */
Image( unsigned int width, unsigned int height, unsigned int depth, unsigned int length, PixelIDValueEnum valueEnum );
/**@}*/
#endif // #ifdef SITK_4D_IMAGES

and 

#include "sitkConfigure.h"

#ifdef SITK_4D_IMAGES
Image::Image( unsigned int Width, unsigned int Height, unsigned int Depth, unsigned int Length, PixelIDValueEnum ValueEnum )
  : m_PimpleImage( NULL )
{
  Allocate ( Width, Height, Depth, Length, ValueEnum, 0 );
}
#endif // #ifdef SITK_4D_IMAGES

(full source: https://github.com/kaspermarstal/SimpleITK/blob/8be437486dce85da271576f866393cd54fe0f865/Code/Common/include/sitkImage.h and https://github.com/kaspermarstal/SimpleITK/blob/8be437486dce85da271576f866393cd54fe0f865/Code/Common/src/sitkImage.cxx)

Why are the #ifdef not triggered by the #define in sitkConfigure.h? It is literally driving me nuts. If I put #define SITK_4D_IMAGES directly in the files the #ifdefs are triggered as expected. Further, if I write #define SITK_4D_IMAGES 1 in sitkConfigure.h and #define SITK_4D_IMAGES 2 in the other files, the compiler complains about redefinitions of SITK_4D_IMAGES, so it can clearly see the definition in the files from where the header is included.

Tested on Ubuntu 14.10 with GCC 4.8.9 and Mac OSX Yosemite with Apple Clang 600.0.56. You are most welcome to git clone -b development --single-branch git://github.com/kaspermarstal/SimpleITK.git to reproduce.

Made a minimal example but was unable to reproduce the bug. The issue must be with SimpleITK's build infrastructure. In case anyone is interested it can be downloaded from dropbox.com/s/zlcnqtx32cq4q22/example.zip?dl=0.

Building instructions:

git clone -b development --single-branch git://github.com/kaspermarstal/SimpleITK.git
mkdir build
cd build
cmake ../SimpleITK/SuperBuild
ccmake .

Set SITK_4D_IMAGES to ON, configure, generate and make -j4. The SuperBuild downloads, builds and installs all dependencies.

Upvotes: 0

Views: 714

Answers (1)

Kasper Marstal
Kasper Marstal

Reputation: 352

The #ifdefs where handled correctly by the compiler. The issue was related to the use of SWIG for wrapping the interface in Python/Java/R/Ruby/Octave/Tcl/Lua/C#. The defines were not passed to SWIG which therefore did not compile what was inside the #ifdef. Adding %include "sitkConfigure.h" to the SWIG .i file fixed the problem.

Upvotes: 1

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