[Maxima-discuss] Interrupting maxima commands in clisp

[Gunter K. <gu...@pe...>]

Dear all,

td;lr: If we could make a clisp-compiled maxima react to the
CTRL_C_EVENT window sends on encountering a Ctrl+C press we could tell
wxMaxima to interrupt the current command on a Ctrl+G press.

I would need help in creating a Ctrl+C handler, though.


The long version of the story:

If on a Linux system the user presses Ctrl+G wxMaxima and Xmaxima send a
SIGINT signal to maxima - and maxima aborts the current command.

On Windows there is no such signal. But maxima comes with a utility
named winkill.exe that writes to a shared memory location maxima offers.
The sbcl and the gcl flavour of maxima by setting an environment
variable can be instructed to create a 2nd thread that polls this memory
location and interrupts the current calculation on incoming signals.

As the lisps evolve that might no more be necessary: If winkill.exe
would issue an

   GenerateConsoleCtrlEvent(CTRL_C_EVENT, m_pid)

an sbcl-based maxima would receive a keyboard interrupt and interrupt
the current program. Unfortunately I cannot test if the same is true
with maxima-gcl.

If maxima is compiled with clisp on linux it reacts to a SIGINT caused
by a Ctrl+C press. On windows it currently doesn't, though. If I issue a
CTRL_BREAK_EVENT instead clisp crashes. Which might be feature that
falls back to an eventual debugger.


Does any of you know if there is a way to make clisp react to the
CTRL_C_EVENT on Windows?

Thanks a lot,
and kind regards,

     Gunter.