On Sat, Oct 29, 2011 at 12:18 PM, Brian Johnson < brianjohnsonhaskellcafe@gmail.com> wrote:
From http://hackage.haskell.org/trac/ghc/wiki/Commentary/Rts/Signals:
"When the interrupt signal is received, the default behaviour of the runtime is to attempt to shut down the Haskell program gracefully. It does this by calling interruptStgRts() in rts/Schedule.chttp://hackage.haskell.org/trac/ghc/browser/rts/Schedule.c (see Commentary/Rts/Scheduler#ShuttingDownhttp://hackage.haskell.org/trac/ghc/wiki/Commentary/Rts/Scheduler#ShuttingDo...). If a second interrupt signal is received, then we terminate the process immediately; this is just in case the normal shutdown procedure failed or hung for some reason, the user is always able to stop the process with two control-C keystrokes"
On further thought, there is something sensible here: the RTS might crash while trying to exit. I propose, for POSIX environments, the following change to SIGINT handling: * SIGINT is transformed into UserInterrupt during normal program execution * Once the RTS is committed to exiting, it resets the signal handler for SIGINT so that any additional control-c causes an immediate exit Makes sense? Brian