1.\" $NetBSD: signal.7,v 1.10 2006/03/28 19:13:04 wiz 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.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the NetBSD 17.\" Foundation, Inc. and its contributors. 18.\" 4. Neither the name of The NetBSD Foundation nor the names of its 19.\" contributors may be used to endorse or promote products derived 20.\" from this software without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 23.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 24.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 25.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 26.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 27.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 28.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 29.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 30.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 31.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 32.\" POSSIBILITY OF SUCH DAMAGE. 33.\" 34.Dd March 28, 2006 35.Dt SIGNAL 7 36.Os 37.Sh NAME 38.Nm signal 39.Nd signal facilities 40.Sh DESCRIPTION 41The 42.Aq Pa signal.h 43header file defines the following signals: 44.Pp 45.Bl -column "99" "SIGVTALARM" "terminate process" -compact 46.It Em "Value" Ta Em "Name" Ta Em "Default Action" Ta Em "Description" 47.It 1 Ta Li SIGHUP Ta "terminate process" Ta "terminal line hangup" 48.It 2 Ta Li SIGINT Ta "terminate process" Ta "interrupt program" 49.It 3 Ta Li SIGQUIT Ta "create core image" Ta "quit program" 50.It 4 Ta Li SIGILL Ta "create core image" Ta "illegal instruction" 51.It 5 Ta Li SIGTRAP Ta "create core image" Ta "trace trap" 52.It 6 Ta Li SIGABRT Ta "create core image" Ta Xr abort 3 53call (formerly 54.Dv SIGIOT ) 55.It 7 Ta Li SIGEMT Ta "create core image" Ta "emulate instruction executed" 56.It 8 Ta Li SIGFPE Ta "create core image" Ta "floating-point exception" 57.It 9 Ta Li SIGKILL Ta "terminate process" Ta "kill program (cannot be caught or ignored)" 58.It 10 Ta Li SIGBUS Ta "create core image" Ta "bus error" 59.It 11 Ta Li SIGSEGV Ta "create core image" Ta "segmentation violation" 60.It 12 Ta Li SIGSYS Ta "create core image" Ta "invalid system call argument" 61.It 13 Ta Li SIGPIPE Ta "terminate process" Ta "write to a pipe with no reader" 62.It 14 Ta Li SIGALRM Ta "terminate process" Ta "real-time timer expired" 63.It 15 Ta Li SIGTERM Ta "terminate process" Ta "software termination signal" 64.It 16 Ta Li SIGURG Ta "discard signal" Ta "urgent condition present on socket" 65.It 17 Ta Li SIGSTOP Ta "stop process" Ta "stop (cannot be caught or ignored)" 66.It 18 Ta Li SIGTSTP Ta "stop process" Ta "stop signal generated from keyboard" 67.It 19 Ta Li SIGCONT Ta "discard signal" Ta "continue after stop" 68.It 20 Ta Li SIGCHLD Ta "discard signal" Ta "child status has changed" 69.It 21 Ta Li SIGTTIN Ta "stop process" Ta "background read attempted from control terminal" 70.It 22 Ta Li SIGTTOU Ta "stop process" Ta "background write attempted to control terminal" 71.It 23 Ta Li SIGIO Ta "discard signal" Ta "I/O is possible on a descriptor (see" 72.Xr fcntl 2 ) 73.It 24 Ta Li SIGXCPU Ta "terminate process" Ta "CPU time limit exceeded (see" 74.Xr setrlimit 2 ) 75.It 25 Ta Li SIGXFSZ Ta "terminate process" Ta "file size limit exceeded (see" 76.Xr setrlimit 2 ) 77.It 26 Ta Li SIGVTALRM Ta "terminate process" Ta "virtual time alarm (see" 78.Xr setitimer 2 ) 79.It 27 Ta Li SIGPROF Ta "terminate process" Ta "profiling timer alarm (see" 80.Xr setitimer 2 ) 81.It 28 Ta Li SIGWINCH Ta "discard signal" Ta "window size change" 82.It 29 Ta Li SIGINFO Ta "discard signal" Ta "status request from keyboard" 83.It 30 Ta Li SIGUSR1 Ta "terminate process" Ta "user-defined signal 1" 84.It 31 Ta Li SIGUSR2 Ta "terminate process" Ta "user-defined signal 2" 85.It 32 Ta Li SIGPWR Ta "discard signal" Ta "power failure/restart" 86.El 87.Pp 88A function that is async-signal-safe is either reentrant or 89non-interruptible by signals. 90This means that they can be used in 91signal handlers 92and in the child of threaded programs after doing 93.Xr fork 2 . 94.Pp 95The following functions are async-signal-safe. 96Any function not listed 97below is unsafe to use in signal handlers. 98.Pp 99.Xr _Exit 2 , 100.Xr _exit 2 , 101.Xr abort 3 , 102.Xr accept 2 , 103.Xr access 2 , 104.\" .Xr aio_error 105.\" .Xr aio_return 106.\" .Xr aio_suspend 107.Xr alarm 3 , 108.Xr bind 2 , 109.Xr cfgetispeed 3 , 110.Xr cfgetospeed 3 , 111.Xr cfsetispeed 3 , 112.Xr cfsetospeed 3 , 113.Xr chdir 2 , 114.Xr chmod 2 , 115.Xr chown 2 , 116.Xr clock_gettime 2 , 117.Xr close 2 , 118.Xr connect 2 , 119.Xr creat 3 , 120.Xr dup 2 , 121.Xr dup2 2 , 122.Xr execle 3 , 123.Xr execve 2 , 124.Xr fchmod 2 , 125.Xr fchown 2 , 126.Xr fcntl 2 , 127.Xr fdatasync 2 , 128.Xr fork 2 , 129.Xr fpathconf 2 , 130.Xr fstat 2 , 131.Xr fsync 2 , 132.Xr ftruncate 2 , 133.Xr getegid 2 , 134.Xr geteuid 2 , 135.Xr getgid 2 , 136.Xr getgroups 2 , 137.Xr getpeername 2 , 138.Xr getpgrp 2 , 139.Xr getpid 2 , 140.Xr getppid 2 , 141.Xr getsockname 2 , 142.Xr getsockopt 2 , 143.Xr getuid 2 , 144.Xr kill 2 , 145.Xr link 2 , 146.Xr listen 2 , 147.Xr lseek 2 , 148.Xr lstat 2 , 149.Xr mkdir 2 , 150.Xr mkfifo 2 , 151.Xr open 2 , 152.Xr pathconf 2 , 153.Xr pause 3 , 154.Xr pipe 2 , 155.Xr poll 2 , 156.\" .Xr posix_trace_event 2 157.\" .Xr pselect 2 158.Xr raise 3 , 159.Xr read 2 , 160.Xr readlink 2 , 161.Xr recv 2 , 162.Xr recvfrom 2 , 163.Xr recvmsg 2 , 164.Xr rename 2 , 165.Xr rmdir 2 , 166.Xr select 2 , 167.Xr sem_post 3 , 168.Xr send 2 , 169.Xr sendmsg 2 , 170.Xr sendto 2 , 171.Xr setgid 2 , 172.Xr setpgid 2 , 173.Xr setsid 2 , 174.Xr setsockopt 2 , 175.Xr setuid 2 , 176.Xr shutdown 2 , 177.Xr sigaction 2 , 178.Xr sigaddset 3 , 179.Xr sigdelset 3 , 180.Xr sigemptyset 3 , 181.Xr sigfillset 3 , 182.Xr sigismember 3 , 183.Xr sleep 3 , 184.Xr signal 3 , 185.Xr sigpause 3 , 186.Xr sigpending 2 , 187.Xr sigprocmask 2 , 188.\" .Xr sigqueue 189.Xr sigset 3 , 190.Xr sigsuspend 2 , 191.Xr sockatmark 3 , 192.Xr socket 2 , 193.Xr socketpair 2 , 194.Xr stat 2 , 195.Xr symlink 2 , 196.Xr sysconf 3 , 197.Xr tcdrain 3 , 198.Xr tcflow 3 , 199.Xr tcflush 3 , 200.Xr tcgetattr 3 , 201.Xr tcgetpgrp 3 , 202.Xr tcsendbreak 3 , 203.Xr tcsetattr 3 , 204.Xr tcsetpgrp 3 , 205.Xr time 3 , 206.Xr timer_getoverrun 2 , 207.Xr timer_gettime 2 , 208.Xr timer_settime 2 , 209.Xr times 3 , 210.Xr umask 2 , 211.Xr uname 3 , 212.Xr unlink 2 , 213.Xr utime 3 , 214.Xr wait 2 , 215.Xr waitpid 2 , 216.Xr write 2 . 217.Sh STANDARDS 218These signals conform to 219.St -p1003.1-90 , 220with the exception of 221.Dv SIGTRAP , 222.Dv SIGEMT , 223.Dv SIGBUS , 224.Dv SIGSYS , 225.Dv SIGURG , 226.Dv SIGIO , 227.Dv SIGXCPU , 228.Dv SIGXFSZ , 229.Dv SIGVTALRM , 230.Dv SIGPROF , 231.Dv SIGWINCH , 232and 233.Dv SIGINFO 234which are Berkeley extensions (available on most 235.Bx Ns \-derived 236systems), and 237.Dv SIGPWR 238which comes from System V. 239.Sh HISTORY 240.Dv SIGPWR 241was introduced in 242.Nx 1.4 . 243.Sh NOTES 244The current 245.Nx 246kernel never generates the 247.Dv SIGPWR 248signal. 249.Sh SEE ALSO 250.Xr kill 1 , 251.Xr kill 2 , 252.Xr ptrace 2 , 253.Xr sigaction 2 , 254.Xr sigaltstack 2 , 255.Xr sigprocmask 2 , 256.Xr sigstack 2 , 257.Xr sigsuspend 2 , 258.Xr fpgetmask 3 , 259.Xr fpsetmask 3 , 260.Xr setjmp 3 , 261.Xr sigblock 3 , 262.Xr siginterrupt 3 , 263.Xr signal 3 , 264.Xr sigpause 3 , 265.Xr sigsetmask 3 , 266.Xr sigsetops 3 , 267.Xr tty 4 268