set print null-stop

set print null-stop

[Alexander Petukhov]

Hello, maling list.
Can't make "set print null-stop" work as written in manual.
For example:

char str[7];
sprintf(str, "i=%i", 0);

(gdb) p str
$1 = "i=0\000\017\377\267"
(gdb) set print null-stop
(gdb) p str
$2 = ""

Does this feature work or I'm doing something wrong?
Another question - is there a corresponding gdm/mi command?

Thank you,
Alexander

Re: set print null-stop

[Jan Kratochvil]

On Sat, 22 Jan 2011 09:40:56 +0100, Alexander Petukhov wrote:
> Hello, maling list.
> Can't make "set print null-stop" work as written in manual.
> For example:
> 
> char str[7];
> sprintf(str, "i=%i", 0);
> 
> (gdb) p str
> $1 = "i=0\000\017\377\267"
> (gdb) set print null-stop
> (gdb) p str
> $2 = ""
> 
> Does this feature work or I'm doing something wrong?

Works for me:

echo 'char str[7]="i=0";main(){}'|gcc -x c - -g;./gdb -nx ./a.out 
GNU gdb (GDB) 7.2.50.20110123-cvs
This GDB was configured as "x86_64-unknown-linux-gnu".
(gdb) p str
$1 = "i=0\000\000\000"
(gdb) set print null-stop
(gdb) p str
$2 = "i=0"


> Another question - is there a corresponding gdm/mi command?

String AFAIK has to be read in MI char-by-char so it is irrelevant.

-var-create a * str
^done,name="a",numchild="7",value="[7]",type="char [7]",has_more="0"
-var-evaluate-expression a
^done,value="[7]"
-var-create - * str[0]
^done,name="var1",numchild="0",value="105 'i'",type="char",has_more="0"
-var-create - * str[1]
^done,name="var2",numchild="0",value="61 '='",type="char",has_more="0"


Regards,
Jan

Re: set print null-stop

[Alexander Petukhov]

Jan, thanks for help.
You won't belive:

pit@debian:~/src/test$ echo 'char str[7]="i=0";main(){}'|gcc -x c - -g;gdb -nx ./a.out 
GNU gdb (GDB) 7.0.1-debian
Copyright (C) 2009 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "i486-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /home/pit/src/test/a.out...done.
(gdb) p str
$1 = "i=0\000\000\000"
(gdb) set print null-stop
(gdb) p str
$2 = ""
(gdb) 

I'll check out latest GDB version as soon as i can, but this particular version (7.0.1, Deban squeeze x86) seems having kind of bug

Alex

On Sun, 23 Jan 2011 14:20:05 +0100
Jan Kratochvil <jan.kratochvil@redhat.com> wrote:

> On Sat, 22 Jan 2011 09:40:56 +0100, Alexander Petukhov wrote:
> > Hello, maling list.
> > Can't make "set print null-stop" work as written in manual.
> > For example:
> > 
> > char str[7];
> > sprintf(str, "i=%i", 0);
> > 
> > (gdb) p str
> > $1 = "i=0\000\017\377\267"
> > (gdb) set print null-stop
> > (gdb) p str
> > $2 = ""
> > 
> > Does this feature work or I'm doing something wrong?
> 
> Works for me:
> 
> echo 'char str[7]="i=0";main(){}'|gcc -x c - -g;./gdb -nx ./a.out 
> GNU gdb (GDB) 7.2.50.20110123-cvs
> This GDB was configured as "x86_64-unknown-linux-gnu".
> (gdb) p str
> $1 = "i=0\000\000\000"
> (gdb) set print null-stop
> (gdb) p str
> $2 = "i=0"
> 
> 
> > Another question - is there a corresponding gdm/mi command?
> 
> String AFAIK has to be read in MI char-by-char so it is irrelevant.
> 
> -var-create a * str
> ^done,name="a",numchild="7",value="[7]",type="char [7]",has_more="0"
> -var-evaluate-expression a
> ^done,value="[7]"
> -var-create - * str[0]
> ^done,name="var1",numchild="0",value="105 'i'",type="char",has_more="0"
> -var-create - * str[1]
> ^done,name="var2",numchild="0",value="61 '='",type="char",has_more="0"
> 
> 
> Regards,
> Jan
> 


-- 
Best regards,
Alexander Petukhov <Alexander.Petukhov@mail.ru>

Re: set print null-stop

[Alexander Petukhov]

well, sorry for  inattention, 7.2 doesn't have this bug and I've found it in the tracker 
http://sourceware.org/bugzilla/show_bug.cgi?id=11049

Thanks for giving a right direction.

By the way, after executing "set print null-stop" in MI mode -data-evaluate-expression also start to
work well, though I understand it's not a good idea to mix MI and not-MI commands 

(gdb) 
-data-evaluate-expression str
^done,value="\"i=0\\000\\000\\000\""
(gdb) 
set print null-stop
&"set print null-stop\n"
^done
(gdb) 
-data-evaluate-expression str
^done,value="\"i=0\""


On Sun, 23 Jan 2011 14:20:05 +0100
Jan Kratochvil <jan.kratochvil@redhat.com> wrote:

> On Sat, 22 Jan 2011 09:40:56 +0100, Alexander Petukhov wrote:
> > Hello, maling list.
> > Can't make "set print null-stop" work as written in manual.
> > For example:
> > 
> > char str[7];
> > sprintf(str, "i=%i", 0);
> > 
> > (gdb) p str
> > $1 = "i=0\000\017\377\267"
> > (gdb) set print null-stop
> > (gdb) p str
> > $2 = ""
> > 
> > Does this feature work or I'm doing something wrong?
> 
> Works for me:
> 
> echo 'char str[7]="i=0";main(){}'|gcc -x c - -g;./gdb -nx ./a.out 
> GNU gdb (GDB) 7.2.50.20110123-cvs
> This GDB was configured as "x86_64-unknown-linux-gnu".
> (gdb) p str
> $1 = "i=0\000\000\000"
> (gdb) set print null-stop
> (gdb) p str
> $2 = "i=0"
> 
> 
> > Another question - is there a corresponding gdm/mi command?
> 
> String AFAIK has to be read in MI char-by-char so it is irrelevant.
> 
> -var-create a * str
> ^done,name="a",numchild="7",value="[7]",type="char [7]",has_more="0"
> -var-evaluate-expression a
> ^done,value="[7]"
> -var-create - * str[0]
> ^done,name="var1",numchild="0",value="105 'i'",type="char",has_more="0"
> -var-create - * str[1]
> ^done,name="var2",numchild="0",value="61 '='",type="char",has_more="0"
> 
> 
> Regards,
> Jan
> 


-- 
Best regards,
Alexander Petukhov <Alexander.Petukhov@mail.ru>

Re: set print null-stop

[Joel Brobecker]

> By the way, after executing "set print null-stop" in MI mode
> -data-evaluate-expression also start to work well, though I understand
> it's not a good idea to mix MI and not-MI commands 

I think that the recommended way of doing this would be to use
the -interpreter-exec command.  For instance, the following should
work (I'm not a GDB/MI expert):

        -interpreter-exec console "set print null-stop"


-- 
Joel