In XCode, open the debug console, then type print ex_strid_to_cstr(34), the 34 is your expect strid_t.
In the gdb console. if you do something like:
(gdb) watch foo->bar->baz
gdb will watch all three locations so you will know if the result of the expression changes for any reason. This is sometimes what you want, and sometimes not. If you know you just want to watch a simple memory location, it is sometimes easier to do:
(gdb) print &(foo->bar->baz)
$1 = (int *) 0x100436f10
(gdb) watch *<HEX address returned from the previous command>
==> watch *0x100436f10
The * in this case tells gdb that you are giving it an address, and not an expression... And of course, without the <>'s... If you want more help on how to use the gdb console, there are docs in /Developer/Documentation/DeveloperTools/gdb/gdb/gdb_toc.html.