On 2008 Jul 18, at 11:45, John Goerzen wrote:
It could also be important if you really don't want other signals handlers doing anything. Say you've got a library that installs a handler for SIGINT that flushes out some buffer and prepares things for the progam to terminate nicely. But in a certain part of your code, you don't want to handle SIGINT at all (or you absolutely want it to be handled only by saying putStrLn "Don't press Ctrl-C now, you dolt!"). Since adding a signal handler could be opaque, this could be quite difficult. With the proposed system, you never know if some module has installed a signal handler, which could be an issue in itself.
This is where you use sigprocmask() in POSIX to simply disallow the signal during your critical section; safer than trusting the user not to interrupt. Your earlier example could be handled by pushing/ popping handlers (and I imagine a typesafe way of doing both of these, e.g. withSignalHandlerDo signal handler block / withSignalMaskDo mask block). -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allbery@kf8nh.com system administrator [openafs,heimdal,too many hats] allbery@ece.cmu.edu electrical and computer engineering, carnegie mellon university KF8NH