Interger over/under flow in C?

Is there a way to implement a portable way of detecting over and underflows in C?

Another thing, my asm code that handles this for now doesnt work either. I cant figure out why not.

asm ("overflow: "
     "xorl %eax, %eax \n"
     "jno O_Ret \n"
     "incl %eax \n"
     "O_Ret: ret\n");

nig_t fuck () {
  nig_t ass = tits + dick;
  if (overflow)
    return piss;
  if (underflow)
    return shit;
  return ass;
}
Now if i could figure out a way for this to work it would only work temporary, as i will need a portable way in the future anyway.

Any help would be appreciated.

>>8
Is not portable.