[BUG] CN cannot be interrupted mid-proof

[podhrmic]

When CN runs a proof, it does not respond to Ctrl+C command and thus cannot be terminated early.

For example (this is the OpenSUT example):

# cd VERSE-OpenSUT/components/mission_protection_system/src
# cn -I include --include=include/wars.h --magic-comment-char-dollar components/instrumentation.c
[1/15]: instrumentation_set_output_trips
[2/15]: instrumentation_handle_command
[3/15]: instrumentation_step_trip
^C[4/15]: instrumentation_step
[5/15]: c_NDEV
[6/15]: c_NVOTE_LOGIC
[7/15]: c_S
[8/15]: c_P
[9/15]: c_T
[10/15]: c_NTRIP
[11/15]: c_TRIP
[12/15]: c_OPERATE
[13/15]: c_BYPASS
[14/15]: c_NMODES
[15/15]: c_NINSTR

Note the ^C got send to the program (after [3/15]: instrumentation_step_trip), but CN didn't terminate until all proofs were completed.

[peterohanley]

instrumentation_step takes a really long time but I wasn't sure if it counted as a bug. It doesn't seem to be doing anything especially weird.

[podhrmic]

It is not that it takes a long time to finish, more the fact that CN is unresponsive during that time.