| Portability | non-portable (requires POSIX) |
|---|---|
| Stability | provisional |
| Maintainer | libraries@haskell.org |
| Safe Haskell | Trustworthy |
System.Posix.Signals
Contents
Description
POSIX signal support
- type Signal = CInt
- nullSignal :: Signal
- internalAbort :: Signal
- sigABRT :: CInt
- realTimeAlarm :: Signal
- sigALRM :: CInt
- busError :: Signal
- sigBUS :: CInt
- processStatusChanged :: Signal
- sigCHLD :: CInt
- continueProcess :: Signal
- sigCONT :: CInt
- floatingPointException :: Signal
- sigFPE :: CInt
- lostConnection :: Signal
- sigHUP :: CInt
- illegalInstruction :: Signal
- sigILL :: CInt
- keyboardSignal :: Signal
- sigINT :: CInt
- killProcess :: Signal
- sigKILL :: CInt
- openEndedPipe :: Signal
- sigPIPE :: CInt
- keyboardTermination :: Signal
- sigQUIT :: CInt
- segmentationViolation :: Signal
- sigSEGV :: CInt
- softwareStop :: Signal
- sigSTOP :: CInt
- softwareTermination :: Signal
- sigTERM :: CInt
- keyboardStop :: Signal
- sigTSTP :: CInt
- backgroundRead :: Signal
- sigTTIN :: CInt
- backgroundWrite :: Signal
- sigTTOU :: CInt
- userDefinedSignal1 :: Signal
- sigUSR1 :: CInt
- userDefinedSignal2 :: Signal
- sigUSR2 :: CInt
- pollableEvent :: Signal
- sigPOLL :: CInt
- profilingTimerExpired :: Signal
- sigPROF :: CInt
- badSystemCall :: Signal
- sigSYS :: CInt
- breakpointTrap :: Signal
- sigTRAP :: CInt
- urgentDataAvailable :: Signal
- sigURG :: CInt
- virtualTimerExpired :: Signal
- sigVTALRM :: CInt
- cpuTimeLimitExceeded :: Signal
- sigXCPU :: CInt
- fileSizeLimitExceeded :: Signal
- sigXFSZ :: CInt
- raiseSignal :: Signal -> IO ()
- signalProcess :: Signal -> ProcessID -> IO ()
- signalProcessGroup :: Signal -> ProcessGroupID -> IO ()
- data Handler
- installHandler :: Signal -> Handler -> Maybe SignalSet -> IO Handler
- data SignalSet
- emptySignalSet :: SignalSet
- fullSignalSet :: SignalSet
- reservedSignals :: SignalSet
- addSignal :: Signal -> SignalSet -> SignalSet
- deleteSignal :: Signal -> SignalSet -> SignalSet
- inSignalSet :: Signal -> SignalSet -> Bool
- getSignalMask :: IO SignalSet
- setSignalMask :: SignalSet -> IO ()
- blockSignals :: SignalSet -> IO ()
- unblockSignals :: SignalSet -> IO ()
- scheduleAlarm :: Int -> IO Int
- getPendingSignals :: IO SignalSet
- awaitSignal :: Maybe SignalSet -> IO ()
- setStoppedChildFlag :: Bool -> IO Bool
- queryStoppedChildFlag :: IO Bool
The Signal type
Specific signals
nullSignal :: Signal
Sending signals
raiseSignal :: Signal -> IO ()
raiseSignal int calls kill to signal the current process
with interrupt signal int.
signalProcess :: Signal -> ProcessID -> IO ()
signalProcess int pid calls kill to signal process pid
with interrupt signal int.
signalProcessGroup :: Signal -> ProcessGroupID -> IO ()
signalProcessGroup int pgid calls kill to signal
all processes in group pgid with interrupt signal int.
Handling signals
data Handler
The actions to perform when a signal is received.
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
Signal sets
data SignalSet
deleteSignal :: Signal -> SignalSet -> SignalSet
inSignalSet :: Signal -> SignalSet -> Bool
The process signal mask
getSignalMask calls sigprocmask to determine the
set of interrupts which are currently being blocked.
setSignalMask :: SignalSet -> IO ()
setSignalMask mask calls sigprocmask with
SIG_SETMASK to block all interrupts in mask.
blockSignals :: SignalSet -> IO ()
blockSignals mask calls sigprocmask with
SIG_BLOCK to add all interrupts in mask to the
set of blocked interrupts.
unblockSignals :: SignalSet -> IO ()
unblockSignals mask calls sigprocmask with
SIG_UNBLOCK to remove all interrupts in mask from the
set of blocked interrupts.
The alarm timer
scheduleAlarm :: Int -> IO Int
scheduleAlarm i calls alarm to schedule a real time
alarm at least i seconds in the future.
Waiting for signals
getPendingSignals :: IO SignalSet
getPendingSignals calls sigpending to obtain
the set of interrupts which have been received but are currently blocked.
awaitSignal :: Maybe SignalSet -> IO ()
awaitSignal iset suspends execution until an interrupt is received.
If iset is Just s, awaitSignal calls sigsuspend, installing
s as the new signal mask before suspending execution; otherwise, it
calls sigsuspend with current signal mask. Note that RTS
scheduler signal (either virtualTimerExpired or realTimeAlarm)
could cause premature termination of this call. It might be necessary to block that
signal before invocation of awaitSignal with blockSignals reservedSignals.
awaitSignal returns when signal was received and processed by a
signal handler, or if the signal could not be caught. If you have
installed any signal handlers with installHandler, it may be wise
to call yield directly after awaitSignal to ensure that the
signal handler runs as promptly as possible.
The NOCLDSTOP flag
setStoppedChildFlag :: Bool -> IO Bool
Tells the system whether or not to set the SA_NOCLDSTOP flag when
installing new signal handlers.
queryStoppedChildFlag :: IO Bool
Queries the current state of the stopped child flag.