Is there a built in swap function in C?

Question

Is there any built in swap function in C which works without using a third variable?

Answer 1

#define swap(T, x, y) \
    {                 \
        T tmp = x;    \
        x = y;        \
        y = tmp;      \
    }

int main()
{
    int a = 10;
    int b = 20;
    printf("a=%d b=%d\n", a, b);
    swap(int, a, b);
    printf("a=%d b=%d\n", a, b);

    return 0;
}