Is there a built-in way to swap two variables in C

Question

I know how to swap 2 variables in c++ , ie you use std::swap(a,b).

question:

Does the C standard library have a similar function

Answer 1

In case of numeric values (at least):

I know this is not an actual or complete answer but until now everyone has been making use of temporary variables so I thought Chris Taylors blog might be relevant to mention, it certainly does remove the need for typeof() etc.

a = a ^ b;
b = a ^ b;
a = a ^ b;

or

a = a + b;
b = a - b;
a = a - b;

In theory I suppose these techniques could be applied to strings and other types as well..

Still only three operations.