void swap(int& x, int& y);
void swap(float& x, float& y) {
swap((int&)x, (int&)y);
}
The best way to do this in C (NOT C++) would be with unions, assuming you know the size of int and float for your platform.
The following would be valid C:
union swappable{
float f;
int i;
}
void swapF(float* x, float* y) {
swappable xs, ys;
xs.f = *x;
ys.f = *y;
swapI(&xs.i, &ys.i);
}
Compilers will optimize all of this to the same machine code.
The strict aliasing rule exists because without it a C compiler has to second guess every load and store, which would have been horribly slow in the 80s and would be even worse now. It still ends up doing that for distinct pointers with the same type, which is why you can explicitly restrict them in newer language versions so the compiler can assume that those pointers wont alias.