🚀 go-pugleaf

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In article <4dkvjk$6q5@lyra.csx.cam.ac.uk> nmm1@cus.cam.ac.uk (Nick
Maclaren) writes: 
<snip>
   But you are making a serious mistake in assuming that run-time systems
   can be implemented to allow everything that the standard permits by
   omission.  They can't.  In THIS case, they can usually preserve the
   stack before calling the atexit() functions.

I think you are bringing up non-issues.

   However, for the advanced paper, think about the following problems:

   What is the effect of an atexit() function calling exit()?  Does it
   restart the atexit() queue, carry on as if the function had returned
   or does it abandon the atexit() queue?

   I chose to do the second, as by far the most user-friendly, but I
   would NEVER write serious code that relied upon that action!

   main() calls setjmp() and then calls exit().  An atexit() function
   calls longjmp() and returns to main().  This repeats (or does it?)

   This is ALSO permitted by omission, but a good run-time system will
   trap it, issue an error message and stop without calling more atexit()
   functions.

Neither of these is permitted in any sense that I understand!
7.10.4.3: If more than one call to the exit function is executed by
a program, the behaviour is undefined. No `permission by omission'
that I can see.

Cheers
Tanmoy
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