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.
l c c l ____ lB c c l.
Signal Value Action Comment
SIGHUP 1 A Hangup detected on controlling terminal
or death of controlling process
SIGINT 2 A Interrupt from keyboard
SIGQUIT 3 A Quit from keyboard
SIGILL 4 A Illegal Instruction
SIGABRT 6 C Abort signal from abort(3)
SIGFPE 8 C Floating point exception
SIGKILL 9 AEF Kill signal SIGSEGV 11 C Invalid
memory reference SIGPIPE 13 A Broken pipe: write to
pipe with no readers SIGALRM 14 A Timer signal from
alarm(2) SIGTERM 15 A Termination signal
SIGUSR1 30,10,16 A User-defined signal 1
SIGUSR2 31,12,17 A User-defined signal 2
SIGCHLD 20,17,18 B Child stopped or terminated
SIGCONT 19,18,25 Continue if stopped
SIGSTOP 17,19,23 DEF Stop process
SIGTSTP 18,20,24 D Stop typed at tty
SIGTTIN 21,21,26 D tty input for background process
SIGTTOU 22,22,27 D tty output for background process
Next various other signals.
l c c l ____ lB c c l.
Signal Value Action Comment
SIGTRAP 5 CG Trace/breakpoint trap
SIGIOT 6 CG IOT trap. A synonym for SIGABRT
SIGEMT 7,-,7 G SIGBUS 10,7,10 AG Bus error
SIGSYS 12,-,12 G Bad argument to routine (SVID)
SIGSTKFLT -,16,- AG Stack fault on coprocessor
SIGURG 16,23,21 BG Urgent condition on socket (4.2
BSD) SIGIO 23,29,22 AG I/O now possible (4.2 BSD)
SIGPOLL AG A synonym for SIGIO (System V)
SIGCLD -,-,18 G A synonym for SIGCHLD
SIGXCPU 24,24,30 AG CPU time limit exceeded (4.2 BSD)
SIGXFSZ 25,25,31 AG File size limit exceeded (4.2 BSD)
SIGVTALRM 26,26,28 AG Virtual alarm clock (4.2 BSD)
SIGPROF 27,27,29 AG Profile alarm clock
SIGPWR 29,30,19 AG Power failure (System V)
SIGINFO 29,-,- G A synonym for SIGPWR
SIGLOST -,-,- AG File lock lost
SIGWINCH 28,28,20 BG Window resize signal (4.3 BSD, Sun)
SIGUNUSED -,31,- AG Unused signal (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, 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 mean-
ings:
A Default action is to terminate the process.
B Default action is to ignore the signal.
C Default action is to dump core.
D Default action is to stop the process.
E Signal cannot be caught.
F Signal cannot be ignored.
G Not a POSIX.1 conformant signal.
CONFORMING TO
POSIX.1
BUGS
SIGIO and SIGLOST have the same value. The latter is com-
mented 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)