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From: Jan Kratochvil <jan.kratochvil@redhat.com>
To: Neven Sajko <nsajko@gmail.com>
Cc: gdb@sourceware.org
Subject: Re: Printing a 2D array in a C program
Date: Fri, 04 Mar 2016 14:42:00 -0000	[thread overview]
Message-ID: <20160304144231.GA7767@host1.jankratochvil.net> (raw)
In-Reply-To: <CAL+bK4NidroyapZhGvtVVsiCbu4=Hz56mF4_oU3iXM-rvqY_xw@mail.gmail.com>

On Fri, 04 Mar 2016 15:27:14 +0100, Neven Sajko wrote:
> In my C program there is a square matrix implemented as an array
> of arrays, which prints nicely in GDB with `info locals`.

I do not understand how that can happen.
You should always provide sample code / example.


> But how can that nice output be accomplished if you are not in
> the function in which the array was declared, but just have it
> passed as a function parameter.

If it is a pointer (as you say C, not C++ reference) you should be able to:
	(gdb) print *thatpointername
Then GDB should IMO print it the same as a local variable is printed.


Printing of C++ vectors of vectors (which is BTW wrong data structure for a 2D
matrix anyway) as a matrix was implemented by Chris Moller as a Python Pretty
printer in some versions of Fedora GDB but it was later discontinued.  The
initial implementation was:
	http://pkgs.fedoraproject.org/cgit/rpms/gdb.git/commit/?id=6068e6305ed7d05b4a919c28aa5bcb737e1f163b
(gdb) p test2
$2 =
  {
    {0      1    }
    {2      3    }
    {4      5    }
 }



Jan


  reply	other threads:[~2016-03-04 14:42 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-04 14:27 Neven Sajko
2016-03-04 14:42 ` Jan Kratochvil [this message]
2016-03-04 16:15   ` Neven Sajko
2016-03-04 17:49     ` Jan Kratochvil
2016-03-04 18:24       ` Pedro Alves
2016-03-04 18:59         ` Jan Kratochvil
2016-03-04 19:16           ` Pedro Alves
2016-03-04 18:34     ` Andreas Schwab
2016-03-04 21:48       ` Neven Sajko
2016-03-04 22:16         ` Andreas Schwab
2016-03-05  0:59           ` Neven Sajko
2016-03-05  8:23             ` Andreas Schwab

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