Why I'm not able to add properties to the collision modifier?

Coding Beginning Blender Code and Development
1

I want to add a simple flag to the structure “CollisionModifierData” within the header “DNA_modifier_types.h” and add a bool controlled in python through a new property in the file “rna_modifier.c”.
But the RNA code is not being generated (errors in compiling). Why?

Thanks in advance

2

SOLVED:

For DNA changes the structs need to aligned so that there are no gaps, which can be done by adding some padding variables.
http://wiki.blender.org/index.php/Dev:2.5/Source/Architecture/DefineProperty#DNA

Example:


        float time_x, time_xnew;    /* cfra time of modifier */
+       char flag, pad[7];
        struct BVHTree *bvhtree;    /* bounding volume hierarchy for this cloth object */