Is there a fast C or C++ standard library function for double precision inverse square root?

Question

I find myself typing

double foo=1.0/sqrt(...);

a lot, and I've heard that modern processors have built-in inverse square root opcodes.

Is there a C or C++ standard library inverse square root function that

1. uses double precision floating point?
2. is as accurate as 1.0/sqrt(...)?
3. is just as fast or faster than the result of 1.0/sqrt(...)?

Answer 1

No. No, there isn't. Not in C++. Nope.