When are infinite loops are useful in PHP?

Question

While reading through the great online PHP tutorials of Paul Hudson he said

Perhaps surprisingly, infinite loops can sometimes be h

Answer 1

Paul Biggar has posted a make script for LaTeX projects which uses an infinite loop to run in the background and continually tries to rebuild the LaTeX sources.

The only way to terminate the script is to kill it externally (e.g. using Ctrl+C).

(Granted, not PHP (Bash, actually) but the same script could well be implemented in PHP instead.)