Re: Hang while scrolling buffer with PNG images

[Richard Stallman]

    Following the instructions I found that an infinite loop occurs at
    three different points:

They all look the same to me: all three times, the infinite loop
occurs in try_scrolling.

    I went through the last one with `step':

`next' is better for this purposes, since it avoids stepping
through subroutines.

    After that it goes on and on without producing some kind of special
    pattern or loop I could identify.

At what line number does the loop begin, and at what line number does
it end?  Where are the end tests in the loop?  Why don't they exit?

What variable is supposed to advance in the loop.  Does it in fact
change from one iteration to the next?  If not, why not?