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Manpage of SIGNAL

SIGNAL

Section: Linux Programmer's Manual (7 )
Updated: 1996-04-14
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NAME

signal - list of available signals  

DESCRIPTION

Linux supports the signals listed below. Several signal numbers are architecture dependent. First the signals described in POSIX.1.

SignalValueActionComment




or death of controlling process
SIGINT 2AInterrupt from keyboard
SIGQUIT 3CQuit from keyboard
SIGILL 4CIllegal Instruction
SIGABRT 6CAbort signal from abort(3)
SIGFPE 8CFloating point exception
SIGKILL 9AEFKill signal
SIGSEGV11CInvalid memory reference
SIGPIPE13ABroken pipe: write to pipe with no readers
SIGALRM14ATimer signal from alarm(2)
SIGTERM15ATermination signal
SIGUSR130,10,16AUser-defined signal 1
SIGUSR231,12,17AUser-defined signal 2
SIGCHLD20,17,18BChild stopped or terminated
SIGCONT19,18,25Continue if stopped
SIGSTOP17,19,23DEFStop process
SIGTSTP18,20,24DStop typed at tty
SIGTTIN21,21,26Dtty input for background process
SIGTTOU22,22,27Dtty output for background process

Next the signals not in POSIX.1 but described in SUSv2.

SignalValueActionComment




SIGPOLLAPollable event (Sys V). Synonym of SIGIO
SIGPROF27,27,29AProfiling timer expired
SIGSYS12,-,12CBad argument to routine (SVID)
SIGTRAP5CTrace/breakpoint trap
SIGURG16,23,21BUrgent condition on socket (4.2 BSD)
SIGVTALRM26,26,28AVirtual alarm clock (4.2 BSD)
SIGXCPU24,24,30CCPU time limit exceeded (4.2 BSD)
SIGXFSZ25,25,31CFile size limit exceeded (4.2 BSD)

(For the cases SIGSYS, SIGXCPU, SIGXFSZ, and on some architectures also SIGBUS, the Linux default action up to now (2.3.27) is A (terminate), while SUSv2 prescribes C (terminate and dump core).)

Next various other signals.

SignalValueActionComment




SIGEMT7,-,7
SIGSTKFLT-,16,-AStack fault on coprocessor
SIGIO23,29,22AI/O now possible (4.2 BSD)
SIGCLD-,-,18A synonym for SIGCHLD
SIGPWR29,30,19APower failure (System V)
SIGINFO29,-,-A synonym for SIGPWR
SIGLOST-,-,-AFile lock lost
SIGWINCH28,28,20BWindow resize signal (4.3 BSD, Sun)
SIGUNUSED-,31,-AUnused signal (will be SIGSYS)

(Here - denotes that a signal is absent; there where three values are given, the first one is usually valid for alpha and sparc, the middle one for i386 and ppc and sh, the last one for mips. Signal 29 is SIGINFO / SIGPWR on an alpha but SIGLOST on a sparc.)

The letters in the "Action" column have the following meanings:

A
Default action is to terminate the process.
B
Default action is to ignore the signal.
C
Default action is to terminate the process and dump core.
D
Default action is to stop the process.
E
Signal cannot be caught.
F
Signal cannot be ignored.
 

CONFORMING TO

POSIX.1  

BUGS

SIGIO and SIGLOST have the same value. The latter is commented out in the kernel source, but the build process of some software still thinks that signal 29 is SIGLOST.  

SEE ALSO

kill(1), kill(2), setitimer(2)


 

Index

NAME
DESCRIPTION
CONFORMING TO
BUGS
SEE ALSO

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