INT32: jmorecfg.h

[Mathieu Malaterre]

Charles Wilson wrote:

> Christopher Faylor wrote:
> 
>> On Tue, Jul 27, 2004 at 10:01:08AM +0100, Dave Korn wrote:
>>
>>> I remember hitting this problem with a cygwin build of libjpeg once.
>>> The correct answer is probably that jmorecfg.h shouldn't arbitrarily
>>> define INT32 globally without first performing an autoconf test to see
>>> if there's something in the system includes that already provides it,
>>> isn't it?
>>
>>
>>
>> Yes.  Just adding more and more ifdef guards around the INT32 definition
>> is not the way to go.
> 
> 
> Unfortunately, the ijg group does not distribute the autoconf source for 
> libjpeg's configure script.  It's on my todo list to really truly 
> autoconfiscate libjpeg (and libtiff) -- which will make things like this 
> easier.  But it's not a very high priority.
> 
> Nor am I all that worked up about this INT32 issue.  jmorecfg.h is 
> present in all builds of libjpeg; I don't understand why INT32 is 
> causing a problem *only* on cygwin.  It seems that you should be seeing 
> the problem on all platforms, or none.  Since your package is showing 
> this behavior only on cygwin, I suspect something wacky in (a) your 
> cygwin environment, or (b) the procedure/configury you're using to build 
> on cygwin (e.g. mixing native and cygwin headers).
> 
> Given that, I'm not going to rush out and fix this right away, because I 
> only have bad choices: (1) add yet another #ifdef hack, or (2) spend a 
> week teasing out and reverse-engineering the autoconfigury source files...

Alright,

	Here is what we did to work around this problem instead of directly 
include jpeglib.h we do:

/* Work-around for a conflict between windows.h and jpeglib.h in cygwin.
If ADDRESS_TAG_BIT is defined then BaseTsd.h has been included and
INT32 has been defined with a typedef, so we must define XMD_H to
prevent the jpeg header from defining it again.  */

# if defined(__CYGWIN__) && defined(ADDRESS_TAG_BIT) && !defined(XMD_H)
#  define XMD_H
#  define VTK_JPEG_XMD_H
# endif
# include <jpeglib.h> 	 # include <jpeglib.h>
# if defined(VTK_JPEG_XMD_H)
#  undef VTK_JPEG_XMD_H
#  undef XMD_H
# endif

http://vtk.org/cgi-bin/viewcvs.cgi/Utilities/vtk_jpeg.h?r1=1.1&r2=1.2&root=VTK

The whole problem was that one can't do:

#include <windows.h>
#include <jpeglib.h>

And according to Christopher, this is "not designed to work well.". Thus 
I don't believe the mistake is in VTK. My guess is if we don't see in 
other plateform is because they -luckily- don't use any typedef INT32.

HTH
Mathieu

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