erfc

/*
 * call-seq:
 *    Math.erfc(x)  => float
 *
 *  Calculates the complementary error function of x.
 */

static VALUE
math_erfc(obj, x)
    VALUE obj, x;
{
    Need_Float(x);
    return rb_float_new(erfc(RFLOAT(x)->value));
}