C99 understands variable-length arrays. They look something like this:
int d1, d2, d3, d4; // runtime-assign those variables int vla[d1][d2][d3][d3];
Now the question is, how to properly cast a pointer to this type when passing it to a function that accepts such a type in a way that makes the compiler happy? The syntax is somewhat unusual:
void func(int d1, int d2, int d3, int d4, int vla[d1][d2][d3][d4]){}
// ...
int * x = malloc();
func(d1, d2, d3, d4, (int (*)[(int)(d2)][(int)(d3)][(int)(d4)])x);
Tested with gcc 4.6.1 and the –std=c99 compiler option. I could not find information about this anywhere on the web so I hope this will help others who wonder how it should be done.