1.\" $NetBSD: signal.7,v 1.17 2014/07/19 14:53:22 roy Exp $ 2.\" 3.\" Copyright (c) 1999 The NetBSD Foundation, Inc. 4.\" All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 15.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 16.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 17.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 18.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 19.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 20.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 21.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 22.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 23.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 24.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 25.\" POSSIBILITY OF SUCH DAMAGE. 26.\" 27.Dd July 18, 2014 28.Dt SIGNAL 7 29.Os 30.Sh NAME 31.Nm signal 32.Nd signal facilities 33.Sh DESCRIPTION 34The 35.In signal.h 36header file defines the following signals: 37.Pp 38.Bl -column ".Sy Value" ".Dv SIGVTALARM" "terminate process" -compact 39.It Sy "Value" Ta Sy "Name" Ta Sy "Default Action" Ta Sy "Description" 40.It 1 Ta Dv SIGHUP Ta "terminate process" Ta "terminal line hangup" 41.It 2 Ta Dv SIGINT Ta "terminate process" Ta "interrupt program" 42.It 3 Ta Dv SIGQUIT Ta "create core image" Ta "quit program" 43.It 4 Ta Dv SIGILL Ta "create core image" Ta "illegal instruction" 44.It 5 Ta Dv SIGTRAP Ta "create core image" Ta "trace trap" 45.It 6 Ta Dv SIGABRT Ta "create core image" Ta Xr abort 3 46call (formerly 47.Dv SIGIOT ) 48.It 7 Ta Dv SIGEMT Ta "create core image" Ta "emulate instruction executed" 49.It 8 Ta Dv SIGFPE Ta "create core image" Ta "floating-point exception" 50.It 9 Ta Dv SIGKILL Ta "terminate process" Ta "kill program (cannot be caught or ignored)" 51.It 10 Ta Dv SIGBUS Ta "create core image" Ta "bus error" 52.It 11 Ta Dv SIGSEGV Ta "create core image" Ta "segmentation violation" 53.It 12 Ta Dv SIGSYS Ta "create core image" Ta "invalid system call argument" 54.It 13 Ta Dv SIGPIPE Ta "terminate process" Ta "write to a pipe with no reader" 55.It 14 Ta Dv SIGALRM Ta "terminate process" Ta "real-time timer expired" 56.It 15 Ta Dv SIGTERM Ta "terminate process" Ta "software termination signal" 57.It 16 Ta Dv SIGURG Ta "discard signal" Ta "urgent condition present on socket" 58.It 17 Ta Dv SIGSTOP Ta "stop process" Ta "stop (cannot be caught or ignored)" 59.It 18 Ta Dv SIGTSTP Ta "stop process" Ta "stop signal generated from keyboard" 60.It 19 Ta Dv SIGCONT Ta "discard signal" Ta "continue after stop (even if blocked or ignored)" 61.It 20 Ta Dv SIGCHLD Ta "discard signal" Ta "child status has changed" 62.It 21 Ta Dv SIGTTIN Ta "stop process" Ta "background read attempted from control terminal" 63.It 22 Ta Dv SIGTTOU Ta "stop process" Ta "background write attempted to control terminal" 64.It 23 Ta Dv SIGIO Ta "discard signal" Ta "I/O is possible on a descriptor (see" 65.Xr fcntl 2 ) 66.It 24 Ta Dv SIGXCPU Ta "terminate process" Ta "CPU time limit exceeded (see" 67.Xr setrlimit 2 ) 68.It 25 Ta Dv SIGXFSZ Ta "terminate process" Ta "file size limit exceeded (see" 69.Xr setrlimit 2 ) 70.It 26 Ta Dv SIGVTALRM Ta "terminate process" Ta "virtual time alarm (see" 71.Xr setitimer 2 ) 72.It 27 Ta Dv SIGPROF Ta "terminate process" Ta "profiling timer alarm (see" 73.Xr setitimer 2 ) 74.It 28 Ta Dv SIGWINCH Ta "discard signal" Ta "window size change" 75.It 29 Ta Dv SIGINFO Ta "discard signal" Ta "status request from keyboard" 76.It 30 Ta Dv SIGUSR1 Ta "terminate process" Ta "user-defined signal 1" 77.It 31 Ta Dv SIGUSR2 Ta "terminate process" Ta "user-defined signal 2" 78.It 32 Ta Dv SIGPWR Ta "discard signal" Ta "power failure/restart" 79.El 80.Pp 81A function that is async-signal-safe is either reentrant or 82non-interruptible by signals. 83This means that they can be used in 84signal handlers 85and in the child of threaded programs after doing 86.Xr fork 2 . 87.Pp 88The following functions are async-signal-safe. 89Any function not listed 90below is unsafe to use in signal handlers. 91.Pp 92.Xr _Exit 2 , 93.Xr _exit 2 , 94.Xr abort 3 , 95.Xr accept 2 , 96.Xr access 2 , 97.\" .Xr aio_error 98.\" .Xr aio_return 99.\" .Xr aio_suspend 100.Xr alarm 3 , 101.Xr bind 2 , 102.Xr cfgetispeed 3 , 103.Xr cfgetospeed 3 , 104.Xr cfsetispeed 3 , 105.Xr cfsetospeed 3 , 106.Xr chdir 2 , 107.Xr chmod 2 , 108.Xr chown 2 , 109.Xr clock_gettime 2 , 110.Xr close 2 , 111.Xr connect 2 , 112.Xr creat 3 , 113.Xr dup 2 , 114.Xr dup2 2 , 115.Xr execle 3 , 116.Xr execve 2 , 117.Xr fchmod 2 , 118.Xr fchown 2 , 119.Xr fcntl 2 , 120.Xr fdatasync 2 , 121.Xr fork 2 , 122.Xr fpathconf 2 , 123.Xr fstat 2 , 124.Xr fsync 2 , 125.Xr ftruncate 2 , 126.Xr getegid 2 , 127.Xr geteuid 2 , 128.Xr getgid 2 , 129.Xr getgroups 2 , 130.Xr getpeername 2 , 131.Xr getpgrp 2 , 132.Xr getpid 2 , 133.Xr getppid 2 , 134.Xr getsockname 2 , 135.Xr getsockopt 2 , 136.Xr getuid 2 , 137.Xr kill 2 , 138.Xr link 2 , 139.Xr listen 2 , 140.Xr lseek 2 , 141.Xr lstat 2 , 142.Xr mkdir 2 , 143.Xr mkfifo 2 , 144.Xr open 2 , 145.Xr pathconf 2 , 146.Xr pause 3 , 147.Xr pipe 2 , 148.Xr poll 2 , 149.\" .Xr posix_trace_event 2 150.\" .Xr pselect 2 151.Xr pthread_mutex_unlock 3 , 152.Xr raise 3 , 153.Xr read 2 , 154.Xr readlink 2 , 155.Xr recv 2 , 156.Xr recvfrom 2 , 157.Xr recvmsg 2 , 158.Xr rename 2 , 159.Xr rmdir 2 , 160.Xr select 2 , 161.Xr sem_post 3 , 162.Xr send 2 , 163.Xr sendmsg 2 , 164.Xr sendto 2 , 165.Xr setgid 2 , 166.Xr setpgid 2 , 167.Xr setsid 2 , 168.Xr setsockopt 2 , 169.Xr setuid 2 , 170.Xr shutdown 2 , 171.Xr sigaction 2 , 172.Xr sigaddset 3 , 173.Xr sigdelset 3 , 174.Xr sigemptyset 3 , 175.Xr sigfillset 3 , 176.Xr sigismember 3 , 177.Xr sleep 3 , 178.Xr signal 3 , 179.Xr sigpause 3 , 180.Xr sigpending 2 , 181.Xr sigprocmask 2 , 182.\" .Xr sigqueue 183.Xr sigset 3 , 184.Xr sigsuspend 2 , 185.Xr sockatmark 3 , 186.Xr socket 2 , 187.Xr socketpair 2 , 188.Xr stat 2 , 189.Xr symlink 2 , 190.Xr sysconf 3 , 191.Xr tcdrain 3 , 192.Xr tcflow 3 , 193.Xr tcflush 3 , 194.Xr tcgetattr 3 , 195.Xr tcgetpgrp 3 , 196.Xr tcsendbreak 3 , 197.Xr tcsetattr 3 , 198.Xr tcsetpgrp 3 , 199.Xr time 3 , 200.Xr timer_getoverrun 2 , 201.Xr timer_gettime 2 , 202.Xr timer_settime 2 , 203.Xr times 3 , 204.Xr umask 2 , 205.Xr uname 3 , 206.Xr unlink 2 , 207.Xr utime 3 , 208.Xr wait 2 , 209.Xr waitpid 2 , 210.Xr write 2 . 211.Sh SEE ALSO 212.Xr kill 1 , 213.Xr kill 2 , 214.Xr ptrace 2 , 215.Xr sigaction 2 , 216.Xr sigaltstack 2 , 217.Xr sigprocmask 2 , 218.Xr sigstack 2 , 219.Xr sigsuspend 2 , 220.Xr fpgetmask 3 , 221.Xr fpsetmask 3 , 222.Xr setjmp 3 , 223.Xr sigblock 3 , 224.Xr siginterrupt 3 , 225.Xr signal 3 , 226.Xr sigpause 3 , 227.Xr sigsetmask 3 , 228.Xr sigsetops 3 , 229.Xr tty 4 230.Sh STANDARDS 231These signals conform to 232.St -p1003.1-90 , 233with the exception of 234.Dv SIGTRAP , 235.Dv SIGEMT , 236.Dv SIGBUS , 237.Dv SIGSYS , 238.Dv SIGURG , 239.Dv SIGIO , 240.Dv SIGXCPU , 241.Dv SIGXFSZ , 242.Dv SIGVTALRM , 243.Dv SIGPROF , 244.Dv SIGWINCH , 245and 246.Dv SIGINFO 247which are Berkeley extensions (available on most 248.Bx Ns \-derived 249systems), and 250.Dv SIGPWR 251which comes from System V. 252.Sh HISTORY 253.Dv SIGPWR 254was introduced in 255.Nx 1.4 . 256.Sh NOTES 257The current 258.Nx 259kernel never generates the 260.Dv SIGPWR 261signal. 262