unix-2.4.0.2: POSIX functionality Source code Contents Index

System.Posix.Signals Portability non-portable (requires POSIX) Stability provisional Maintainer libraries@haskell.org

Contents The Signal type Specific signals Sending signals Handling signals Signal sets The process signal mask The alarm timer Waiting for signals The NOCLDSTOP flag

Description

POSIX signal support

Synopsis

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 = Default | Ignore | Catch (IO ()) | CatchOnce (IO ()) installHandler :: Signal -> Handler -> Maybe SignalSet -> IO Handler data SignalSet emptySignalSet :: SignalSet fullSignalSet :: 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

type Signal = CInt Source

Specific signals

nullSignal :: Signal Source

internalAbort :: Signal Source

sigABRT :: CInt Source

realTimeAlarm :: Signal Source

sigALRM :: CInt Source

busError :: Signal Source

sigBUS :: CInt Source

processStatusChanged :: Signal Source

sigCHLD :: CInt Source

continueProcess :: Signal Source

sigCONT :: CInt Source

floatingPointException :: Signal Source

sigFPE :: CInt Source

lostConnection :: Signal Source

sigHUP :: CInt Source

illegalInstruction :: Signal Source

sigILL :: CInt Source

keyboardSignal :: Signal Source

sigINT :: CInt Source

killProcess :: Signal Source

sigKILL :: CInt Source

openEndedPipe :: Signal Source

sigPIPE :: CInt Source

keyboardTermination :: Signal Source

sigQUIT :: CInt Source

segmentationViolation :: Signal Source

sigSEGV :: CInt Source

softwareStop :: Signal Source

sigSTOP :: CInt Source

softwareTermination :: Signal Source

sigTERM :: CInt Source

keyboardStop :: Signal Source

sigTSTP :: CInt Source

backgroundRead :: Signal Source

sigTTIN :: CInt Source

backgroundWrite :: Signal Source

sigTTOU :: CInt Source

userDefinedSignal1 :: Signal Source

sigUSR1 :: CInt Source

userDefinedSignal2 :: Signal Source

sigUSR2 :: CInt Source

pollableEvent :: Signal Source

sigPOLL :: CInt Source

profilingTimerExpired :: Signal Source

sigPROF :: CInt Source

badSystemCall :: Signal Source

sigSYS :: CInt Source

breakpointTrap :: Signal Source

sigTRAP :: CInt Source

urgentDataAvailable :: Signal Source

sigURG :: CInt Source

virtualTimerExpired :: Signal Source

sigVTALRM :: CInt Source

cpuTimeLimitExceeded :: Signal Source

sigXCPU :: CInt Source

fileSizeLimitExceeded :: Signal Source

sigXFSZ :: CInt Source

Sending signals

raiseSignal :: Signal -> IO () Source

raiseSignal int calls kill to signal the current process with interrupt signal int.

signalProcess :: Signal -> ProcessID -> IO () Source

signalProcess int pid calls kill to signal process pid with interrupt signal int.

signalProcessGroup :: Signal -> ProcessGroupID -> IO () Source

signalProcessGroup int pgid calls kill to signal all processes in group pgid with interrupt signal int.

Handling signals

data Handler Source

The actions to perform when a signal is received. Constructors Default Ignore Catch (IO ()) CatchOnce (IO ()) Instances Typeable Handler

installHandler Source

:: Signal -> Handler -> Maybe SignalSet other signals to block -> IO Handler old handler 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 Source

emptySignalSet :: SignalSet Source

fullSignalSet :: SignalSet Source

addSignal :: Signal -> SignalSet -> SignalSet Source

deleteSignal :: Signal -> SignalSet -> SignalSet Source

inSignalSet :: Signal -> SignalSet -> Bool Source

The process signal mask

getSignalMask :: IO SignalSet Source

getSignalMask calls sigprocmask to determine the set of interrupts which are currently being blocked.

setSignalMask :: SignalSet -> IO () Source

setSignalMask mask calls sigprocmask with SIG_SETMASK to block all interrupts in mask.

blockSignals :: SignalSet -> IO () Source

blockSignals mask calls sigprocmask with SIG_BLOCK to add all interrupts in mask to the set of blocked interrupts.

unblockSignals :: SignalSet -> IO () Source

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 Source

scheduleAlarm i calls alarm to schedule a real time alarm at least i seconds in the future.

Waiting for signals

getPendingSignals :: IO SignalSet Source

getPendingSignals calls sigpending to obtain the set of interrupts which have been received but are currently blocked.

awaitSignal :: Maybe SignalSet -> IO () Source

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 pause. awaitSignal returns on receipt of a signal. 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 Source

Tells the system whether or not to set the SA_NOCLDSTOP flag when installing new signal handlers.

queryStoppedChildFlag :: IO Bool Source

Queries the current state of the stopped child flag.

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