what does “= preserve do” mean in gdb

Question

following this tutorial about C and gdb . It is certainly a helpful tutorial but they started out with examples like this:

(gdb) print a
$1 = {1, 2, 3}
(gdb) ptype a
type = int [3]

and then suddenly started displaying this sequence of

= preserve do
  :escaped
    (gdb) x/4xb a + 1
    0x7fff5fbff570: 0x02  0x00  0x00  0x00

in their examples without explaining what it was. I cannot understand or recreate it. A google search of "gdb preserve do" points back to the same site. I can continue following without it but I'm curious what the = preserve do is all about?

Answer 1

without explaining what it was

It's a bug in their HTML formatting (markup), and has nothing to do with GDB.