title: What does standard say about cmath functions like std::pow, std::log etc?
body: <p>Does the standard guarantee that functions return the exact same result across all implementations?</p>
  
  <p>Take for example <code>pow(float,float)</code> for 32bit IEEE floats. Is the result across all implementations identical if the same two floats are passed in?</p>
  
  <p>Or is there some flexibility that the standard allows with regard to tiny differences depending on the algorithm used to implement <code>pow</code>?</p>