如何判断整数相加是否溢出

CSAPP

int tadd_ok(int x, int y)
{
    int sum = x + y;
    int neg_over = x < 0 && y < 0 && sum >= 0;
    int pos_over = x >= 0 && y >= 0 && sum < 0;
    return !neg_over && !pos_over;
}

python

    register long a, b, x;
    CONVERT_TO_LONG(v, a);
    CONVERT_TO_LONG(w, b);
    x = a + b;
    if ((x^a) >= 0 || (x^b) >= 0)
        return PyInt_FromLong(x);