[magick-users] Backslashes and percentage signs in image comments

[Felix Hagemann]

Hello,
I try to add image comments that contain backslashes and/or percentage
signs but I am not having much success. Consider the following
example:

$ convert -comment 'test\123\456\n%%w' logo: png:- | identify \
-format '%c' png:-

Its output for ImageMagick 6.2.3 and some earlier versions, which were
available for testing:

test\123\456
640

For ImageMagick 6.2.4:

test1346
641

So my questions are:

- How can I escape the backslashes so that they get included in the
comment with the newer version? I tried double, triple backslashes,
combinations with %-signs and some more. Backslashes only seem to eat
away the second character to their right, parsing the string right to
left.

- In both versions using a % to escape the special meaning of the
following % as suggested in some documentation does not work. How to 
include a percentage in a comment?

Can somebody point me to some documentation that would help me resolve
those issues? I haven't found anything. Or maybe just point me to the
source file in which I can find the parsing routine so I can have a
look myself?

Thanks in advance!
Felix