has_more="0" with pretty-printer installed

has_more="0" with pretty-printer installed

[Yao Qi]

Hi,
I find the output of "-var-create" in gdb.python/py-mi.exp confuses me a 
little,

-var-create container @ c^M
^done,name="container",numchild="0",value="{...}",type="zzz_type",thread-id="1",dynamic="1",has_more="0"^M
                                                  ^^^^^^^^^^^^
(gdb) ^M
PASS: gdb.python/py-mi.exp: create container varobj

On this test, pretty-printer is installed, and 'c' is of type 'zzz_type',

struct container
{
   string name;
   int len;
   int *elements;
};

typedef struct container zzz_type;

IIUC, has_more should be 1 here, because c has three fields.  Am I 
missing something?  The minimum steps to reproduce this problem are:

$ ./gdb ./testsuite/gdb.python/py-mi
(gdb) b main
Breakpoint 1 at 0x80485ee: file 
../../../../git/gdb/testsuite/gdb.python/py-prettyprint.c, line 264.
(gdb) run
Starting program: 
/home/yao/Source/gnu/gdb/build-git/x86/gdb/testsuite/gdb.python/py-mi

Breakpoint 1, main () at 
../../../../git/gdb/testsuite/gdb.python/py-prettyprint.c:264
264       string x = make_string ("this is x");
(gdb) python exec (open 
('gdb/git/gdb/testsuite/gdb.python/py-prettyprint.py').read ())
(gdb) interpreter-exec mi "-enable-pretty-printing"
^done
(gdb) interpreter-exec mi "-var-create container @ c"
^done,name="container",numchild="0",value="{...}",type="zzz_type",thread-id="1",dynamic="1",has_more="1"
                                                  ^^^^^^^^^^^
// note: at this point, has_more is 1, which looks right to me

(gdb) b 329
Breakpoint 2 at 0x804871e: file 
../../../../git/gdb/testsuite/gdb.python/py-prettyprint.c, line 329.
(gdb) c
Continuing.

Breakpoint 2, main () at 
../../../../git/gdb/testsuite/gdb.python/py-prettyprint.c:329
329       add_item (&c, 23);            /* MI breakpoint here */
(gdb) interpreter-exec mi "-var-create container1 @ c"
^done,name="container1",numchild="0",value="{...}",type="zzz_type",thread-id="1",dynamic="1",has_more="0"
                                                  ^^^^^^^^^^^^

// has_more becomes 0.

-- 
Yao (齐尧)

Re: has_more="0" with pretty-printer installed

[Yao Qi]

On 11/11/2013 03:24 PM, Yao Qi wrote:
> (gdb) b 329
> Breakpoint 2 at 0x804871e: file
> ../../../../git/gdb/testsuite/gdb.python/py-prettyprint.c, line 329.
> (gdb) c
> Continuing.
>
> Breakpoint 2, main () at
> ../../../../git/gdb/testsuite/gdb.python/py-prettyprint.c:329
> 329       add_item (&c, 23);            /* MI breakpoint here */

You should set breakpoint on line 328 to reproduce it.
A blank line is added in my gdb.python/py-prettyprint.c.

-- 
Yao (齐尧)

Re: has_more="0" with pretty-printer installed

[Yao Qi]

On 11/11/2013 04:05 PM, Elmenthaler, Jens wrote:
> Since dynamic is true, there is a pretty printer registered for zzz_type or struct container. Struct container looks like a collection, so the purpose of the pretty printer probably is to show its elements as children, not the struct's data members itself. If nobody add elements to the container, the number of its children will be 0. Just a guess, of course, ...

Your are right, the pretty printer shows field "elements" of "struct
container" as children, instead of "struct container"'s fields.  Thanks!

-- 
Yao (齐尧)