[Bf-committers] Casting arrays (matrices)

[Ton Roosendaal]

Hi,

It caused warnings in compiling at osx and other unices. Loads and  
loads of them! I don't know how it compiled well at NaN...

The commits go to bf-blender-cvs maillist, there I wrote some more info:

   Modified files:
     blender/source/blender/blenlib BLI_arithb.h
     blender/source/blender/blenlib/intern arithb.c

   Log:
   - removed the 'const' from arithb function declarations. it caused
     the myriad of warnings people complained about so long.

     after careful consulting & reading I could not find a good reason
     for this const stuff, apart from a sort-of comment to indicate
     this array (matrix) pointer cannot be changed. Well, doh! you
     should not do that with a float mat[][3] anyway!

I can imagine it is useful to add 'const' in a function as some  
information for other users. But doing it here, in basic matrix  
calculus calls, is just over the top. Especially when it generates  
warnings...

-Ton-



On Wednesday, Jul 2, 2003, at 22:07 Europe/Amsterdam, Maarten Gribnau  
wrote:

> Hi Ton
>
>> Reading the arithb.c code, I found that someone (NaN) has included a  
>> lot of 'const' variables in the function declarations. I have  
>> absolutely no clue what it's good for. Originally, the code worked  
>> fine without, as still is in the MTC_matrixops.c version in  
>> source/blender/blenlib/
>>
>> I've removed the 'const' everywhere from arithb.c. The code compiles  
>> quite a lot faster, with only a few and more useful warnings left.
> How does the const cause trouble?
> The const is actually useful. It tells you the function is not going  
> to modify the variable (usually pointers and references in C++) passed  
> to it. It makes the variable an "in only" variable.
>
> Maarten
>
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Ton Roosendaal  Blender Foundation ton@blender.org  
http://www.blender.org