Copyright	(c) The University of Glasgow 2002
License	BSD-style (see the file libraries/base/LICENSE)
Maintainer	[email protected]
Stability	provisional
Portability	non-portable (requires POSIX)
Safe Haskell	Trustworthy
Language	Haskell2010

The Signal type

type Signal = CInt Source

Specific signals

nullSignal :: Signal Source

internalAbort :: Signal Source

Alias for sigABRT.

sigABRT :: CInt Source

Process abort signal.

realTimeAlarm :: Signal Source

Alias for sigALRM.

sigALRM :: CInt Source

Alarm clock.

busError :: Signal Source

Alias for sigBUS.

sigBUS :: CInt Source

Access to an undefined portion of a memory object.

processStatusChanged :: Signal Source

Alias for sigCHLD.

sigCHLD :: CInt Source

Child process terminated, stopped, or continued.

continueProcess :: Signal Source

Alias for sigCONT.

sigCONT :: CInt Source

Continue executing, if stopped.

floatingPointException :: Signal Source

Alias for sigFPE.

sigFPE :: CInt Source

Erroneous arithmetic operation.

lostConnection :: Signal Source

Alias for sigHUP.

sigHUP :: CInt Source

Hangup.

illegalInstruction :: Signal Source

Alias for sigILL.

sigILL :: CInt Source

Illegal instruction.

keyboardSignal :: Signal Source

Alias for sigINT.

sigINT :: CInt Source

Terminal interrupt signal.

killProcess :: Signal Source

Alias for sigKILL.

sigKILL :: CInt Source

Kill (cannot be caught or ignored).

openEndedPipe :: Signal Source

Alias for sigPIPE.

sigPIPE :: CInt Source

Write on a pipe with no one to read it.

keyboardTermination :: Signal Source

Alias for sigQUIT.

sigQUIT :: CInt Source

Terminal quit signal.

segmentationViolation :: Signal Source

Alias for sigSEGV.

sigSEGV :: CInt Source

Invalid memory reference.

softwareStop :: Signal Source

Alias for sigSTOP.

sigSTOP :: CInt Source

Stop executing (cannot be caught or ignored).

softwareTermination :: Signal Source

Alias for sigTERM.

sigTERM :: CInt Source

Termination signal.

keyboardStop :: Signal Source

Alias for sigTSTP.

sigTSTP :: CInt Source

Terminal stop signal.

backgroundRead :: Signal Source

Alias for sigTTIN.

sigTTIN :: CInt Source

Background process attempting read.

backgroundWrite :: Signal Source

Alias for sigTTOU.

sigTTOU :: CInt Source

Background process attempting write.

userDefinedSignal1 :: Signal Source

Alias for sigUSR1.

sigUSR1 :: CInt Source

User-defined signal 1.

userDefinedSignal2 :: Signal Source

Alias for sigUSR2.

sigUSR2 :: CInt Source

User-defined signal 2.

pollableEvent :: Signal Source

Alias for sigPOLL.

sigPOLL :: CInt Source

Pollable event.

profilingTimerExpired :: Signal Source

Alias for sigPROF.

sigPROF :: CInt Source

Profiling timer expired.

badSystemCall :: Signal Source

Alias for sigSYS.

sigSYS :: CInt Source

Bad system call.

breakpointTrap :: Signal Source

Alias for sigTRAP.

sigTRAP :: CInt Source

Trace/breakpoint trap.

urgentDataAvailable :: Signal Source

Alias for sigURG.

sigURG :: CInt Source

High bandwidth data is available at a socket.

virtualTimerExpired :: Signal Source

Alias for sigVTALRM.

sigVTALRM :: CInt Source

Virtual timer expired.

cpuTimeLimitExceeded :: Signal Source

Alias for sigXCPU.

sigXCPU :: CInt Source

CPU time limit exceeded.

fileSizeLimitExceeded :: Signal Source

Alias for sigXFSZ.

sigXFSZ :: CInt Source

File size limit exceeded.

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.

data SignalInfo Source

Information about a received signal (derived from siginfo_t).

Since: unix-2.7.0.0

data SignalSpecificInfo Source

Information specific to a particular type of signal (derived from siginfo_t).

Since: unix-2.7.0.0

installHandler Source

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

reservedSignals :: SignalSet Source

A set of signals reserved for use by the implementation. In GHC, this will normally include either sigVTALRM or sigALRM.

addSignal :: Signal -> SignalSet -> SignalSet infixr 9 Source

deleteSignal :: Signal -> SignalSet -> SignalSet infixr 9 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 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 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.