[pdftex] Help! pdfTeX: Get black squares (cursors) in @example text

[pawcoo]

John Blevin wrote:
> In pdfTeX, when I include an @example/@end example of some
> source code, when the line is long (say, >70 chars) there
> is an annoying black square character (like a solid cursor)
> at the end of the line.  How to avoid them???
> 
> This is with:
>     pdfTeX (Web2C 7.4.5) 3.14159-1.10b
>     kpathsea version 3.4.5
> 

John Culleton wrote:
 > Or you can just set \overfullrule to 0pt and let the line
 > run into the margin.

But actually changing \overfullrule to 0pt do not solve the problem. You 
should rather play with \tolerance, \hfuzz, \hbadness, \raggedright (and 
many others) to make a nice paragraph. Chapter 14 and 15 of The TeXBook 
says the whole story.

In fact some macro packages shuts up this annoying rule setting 
\overfullrule to 0pt but it is compensated with some optimizing 
mechanisms. Setting \overfullrule to zero in plain is risky if You care 
about nice paragraphs :)

Regards, Pawel