size?

/*
 * call-seq:
 *    File.size?(file_name)   => Integer or nil
 *
 * Returns +nil+ if +file_name+ doesn't exist or has zero size, the size of the
 * file otherwise.
 */

static VALUE
test_s(obj, fname)
    VALUE obj, fname;
{
    struct stat st;

    if (rb_stat(fname, &st) < 0) return Qnil;
    if (st.st_size == 0) return Qnil;
    return OFFT2NUM(st.st_size);
}