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'\" t
.\" Copyright (c) 1993 by Thomas Koenig (ig25@rz.uni-karlsruhe.de)
.\"
.\" Permission is granted to make and distribute verbatim copies of this
.\" manual provided the copyright notice and this permission notice are
.\" preserved on all copies.
.\"
.\" Permission is granted to copy and distribute modified versions of this
.\" manual under the conditions for verbatim copying, provided that the
.\" entire resulting derived work is distributed under the terms of a
.\" permission notice identical to this one
.\"
.\" Since the Linux kernel and libraries are constantly changing, this
.\" manual page may be incorrect or out-of-date. The author(s) assume no
.\" responsibility for errors or omissions, or for damages resulting from
.\" the use of the information contained herein. The author(s) may not
.\" have taken the same level of care in the production of this manual,
.\" which is licensed free of charge, as they might when working
.\" professionally.
.\"
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
.\" License.
.\" Modified Sat Jul 24 17:34:08 1993 by Rik Faith (faith@cs.unc.edu)
.\" Modified Sun Jan 7 01:41:27 1996 by Andries Brouwer (aeb@cwi.nl)
.\" Modified Sun Apr 14 12:02:29 1996 by Andries Brouwer (aeb@cwi.nl)
.\" Modified Sat Nov 13 16:28:23 1999 by Andries Brouwer (aeb@cwi.nl)
.\"
.TH SIGNAL 7 "April 14, 1996" "Linux 1.3.88" "Linux Programmer's Manual"
.SH NAME
signal \- list of available signals
.SH DESCRIPTION
Linux supports the signals listed below. Several signal numbers
are architecture dependent. First the signals described in POSIX.1.
.sp
.PP
.TS
l c c l
____
lB c c l.
Signal Value Action Comment
SIGHUP \01 A Hangup detected on controlling terminal
or death of controlling process
SIGINT \02 A Interrupt from keyboard
SIGQUIT \03 C Quit from keyboard
SIGILL \04 C Illegal Instruction
SIGABRT \06 C Abort signal from \fIabort\fP(3)
SIGFPE \08 C Floating point exception
SIGKILL \09 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 \fIalarm\fP(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
.TE
Next the signals not in POSIX.1 but described in SUSv2.
.sp
.PP
.TS
l c c l
____
lB c c l.
Signal Value Action Comment
SIGBUS 10,7,10 C Bus error (bad memory access)
SIGPOLL A Pollable event (Sys V). Synonym of SIGIO
SIGPROF 27,27,29 A Profiling timer expired
SIGSYS 12,\-,12 C Bad argument to routine (SVID)
SIGTRAP 5 C Trace/breakpoint trap
SIGURG 16,23,21 B Urgent condition on socket (4.2 BSD)
SIGVTALRM 26,26,28 A Virtual alarm clock (4.2 BSD)
SIGXCPU 24,24,30 C CPU time limit exceeded (4.2 BSD)
SIGXFSZ 25,25,31 C File size limit exceeded (4.2 BSD)
.TE
(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.
.sp
.PP
.TS
l c c l
____
lB c c l.
Signal Value Action Comment
SIGIOT 6 C IOT trap. A synonym for SIGABRT
SIGEMT 7,\-,7
SIGSTKFLT \-,16,\- A Stack fault on coprocessor
SIGIO 23,29,22 A I/O now possible (4.2 BSD)
SIGCLD \-,\-,18 A synonym for SIGCHLD
SIGPWR 29,30,19 A Power failure (System V)
SIGINFO 29,\-,\- A synonym for SIGPWR
SIGLOST \-,\-,\- A File lock lost
SIGWINCH 28,28,20 B Window resize signal (4.3 BSD, Sun)
SIGUNUSED \-,31,\- A Unused signal (will be SIGSYS)
.TE
(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
.B SIGINFO
/
.B SIGPWR
on an alpha but
.B SIGLOST
on a sparc.)
.PP
The letters in the "Action" column have the following meanings:
.IP A
Default action is to terminate the process.
.IP B
Default action is to ignore the signal.
.IP C
Default action is to terminate the process and dump core.
.IP D
Default action is to stop the process.
.IP E
Signal cannot be caught.
.IP F
Signal cannot be ignored.
.SH "CONFORMING TO"
POSIX.1
.SH BUGS
.B SIGIO
and
.B 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
.BR SIGLOST .
.SH "SEE ALSO"
.BR kill (1),
.BR kill (2),
.BR setitimer (2)
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