malloc error for newbie

[John Machin]

On Jul 7, 4:59 pm, David <dwarnol... at suddenlink.net> wrote:
> Hi,
>
> Very new to python. When I uncomment the line
> #        self.im.putpalette(mkpalette())

Try to focus in on where the nasty is happening:

   p = mkpalette()
   # self.im.putpalette(p)


> in the following code, I get the error:
>
> python $ ./mandelbrot.py
> Python(2860) malloc: ***  Deallocation of a pointer not malloced:
> 0xff000000; This could be a double free(), or free() called with the
> middle of an allocated block; Try setting environment variable
> MallocHelp to see tools to help debug
>
> I don't have the expertise to get by this error. Can someone help?
>
> Thanks.
>
> #! /usr/local/bin/python
> # Filename: mandelbrot.py
>
> import Image, ImagePalette

Read the docs: http://effbot.org/imagingbook/imagepalette.htm

They imply that len(palette) should be 769 (256*3)

>
> def mkpalette():
>     global palette

Nothing to do with your problem, but lose the above line, and examine
carefully whatever induced you to include it.

>     palette = [0,0,0]


>     for i in range(256):
>         palette.extend([i*5%200+55,i*7%200+55,i*11%200+55])
>     return palette

So now len(palette) == 257*3 instead of 256*3; this may be your
problem.


HTH,
John