What does ^ mean in PHP?

Question

I came across this line of code in an application I am revising:

substr($sometext1 ^ $sometext2, 0, 512);

What does the ^ mean

Answer 1

^ is the bitwise exclusive OR operator. For each bit in a value, it looks to see if that bit is the same in the other value; if it is the same, a 0 is output in its place, otherwise a 1 is output. For example:

  00001111
^ 01010101
  --------
  01011010