Re: Using the GNU GMP Library for Bignums in Emacs

[Richard Stallman]

[[[ To any NSA and FBI agents reading my email: please consider    ]]]
[[[ whether defending the US Constitution against all enemies,     ]]]
[[[ foreign or domestic, requires you to follow Snowden's example. ]]]

  > Allowing immediate quitting from arbitrary points in execution causes 
problems 

Immediate quitting was never allowed from arbitrary points in execution.
Only in places where immediate_quit was nonzero.
Those were generally code whose side effects would not matter
unless they were allowed to finish.

  > In the old days we could assume that execution order at the
  > machine level was the same order as in the C program source code,
  > which meant that as long as the C source code did things in the
  > right order Emacs could survive immediate quitting. That
  > assumption is no longer true.

That problem exists in theory.  Did the problem actually occur?

  >  To do things safely now, we need to either (1) add critical
  > sections to Emacs where appropriate, or (2) test the quit flag at
  > appropriate intervals

... in each and every place where immediate_quit was formerly used.

                           In practice (2) is easier to implement and
  > to maintain.

If (2) means to check for quitting as needed in each and every place
code where immediate_quit was formerly used, that would thoroughly do
the job, but did we handle all of those places?



-- 
Dr Richard Stallman
President, Free Software Foundation (https://gnu.org, https://fsf.org)
Internet Hall-of-Famer (https://internethalloffame.org)
Skype: No way! See https://stallman.org/skype.html.