inspect

/*
 * call-seq:
 *   ios.inspect   => string
 *
 * Return a string describing this IO object.
 */

static VALUE
rb_io_inspect(obj)
    VALUE obj;
{
    rb_io_t *fptr;
    char *buf;
    const char *cname, *st = "";
    long len;

    fptr = RFILE(rb_io_taint_check(obj))->fptr;
    if (!fptr || !fptr->path) return rb_any_to_s(obj);
    cname = rb_obj_classname(obj);
    len = strlen(cname) + strlen(fptr->path) + 5;
    if (!(fptr->f || fptr->f2)) {
        st = " (closed)";
        len += 9;
    }
    buf = ALLOCA_N(char, len);
    snprintf(buf, len, "#<%s:%s%s>", cname, fptr->path, st);
    return rb_str_new2(buf);
}