The actions to perform when a signal is received.
Extracts the Fd from a Handle. This function has the side effect of closing the Handle and flushing its write buffer, if necessary.
Converts an Fd into a Handle that can be used with the standard Haskell IO library (see System.IO).
GHC only: this function has the side effect of putting the Fd into non-blocking mode (O_NONBLOCK) due to the way the standard IO library implements multithreaded I/O.
installHandler int handler iset calls sigaction to install an interrupt handler for signal int. If handler is Default, SIG_DFL is installed; if handler is Ignore, SIG_IGN is installed; if handler is Catch action, a handler is installed which will invoke action in a new thread when (or shortly after) the signal is received. If iset is Just s, then the sa_mask of the sigaction structure is set to s; otherwise it is cleared. The previously installed signal handler for int is returned