1.\" Copyright (c) 1983, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)psignal.3 8.2 (Berkeley) 2/27/95 33.\" $FreeBSD: src/lib/libc/gen/psignal.3,v 1.10.2.5 2003/03/15 15:11:05 trhodes Exp $ 34.\" $DragonFly: src/lib/libc/gen/psignal.3,v 1.3 2003/10/14 23:13:05 dillon Exp $ 35.\" 36.Dd February 27, 1995 37.Dt PSIGNAL 3 38.Os 39.Sh NAME 40.Nm psignal , 41.Nm strsignal , 42.Nm sys_siglist , 43.Nm sys_signame 44.Nm sys_nsig 45.Nd system signal messages 46.Sh LIBRARY 47.Lb libc 48.Sh SYNOPSIS 49.In signal.h 50.Ft void 51.Fn psignal "unsigned sig" "const char *s" 52.Vt extern const char * const sys_siglist[] ; 53.Vt extern const char * const sys_signame[] ; 54.Vt extern const int sys_nsig ; 55.In string.h 56.Ft "char *" 57.Fn strsignal "int sig" 58.Sh DESCRIPTION 59The 60.Fn psignal 61and 62.Fn strsignal 63functions locate the descriptive message 64string for a signal number. 65.Pp 66The 67.Fn strsignal 68function accepts a signal number argument 69.Fa sig 70and returns a pointer to the corresponding message string. 71.Pp 72The 73.Fn psignal 74function accepts a signal number argument 75.Fa sig 76and writes it to the standard error. 77If the argument 78.Fa s 79is 80.Pf non- Dv NULL 81and does not point to the null character, 82.Fa s 83is written to the standard error file descriptor 84prior to the message string, 85immediately followed by a colon and a space. 86If the signal number is not recognized 87.Pq Xr sigaction 2 , 88the string 89.Dq "Unknown signal 90is produced. 91.Pp 92The message strings can be accessed directly 93through the external array 94.Va sys_siglist , 95indexed by recognized signal numbers. 96The external array 97.Va sys_signame 98is used similarly and 99contains short, lower-case abbreviations for signals 100which are useful for recognizing signal names 101in user input. 102The external variable 103.Va sys_nsig 104contains a count of the strings in 105.Va sys_siglist 106and 107.Va sys_signame . 108Note that the defined variable 109.Dv NSIG 110will typically be the same as 111.Va sys_nsig , 112but might be different due to newer or older kernels and newer or 113older libc libraries. For maximum portability you must use 114.Va sys_nsig 115to limit-check the above arrays. Additionally, you should check 116for 117.Dv NULL 118array entries and generate a generic signal name in those cases. 119.Sh SEE ALSO 120.Xr sigaction 2 , 121.Xr perror 3 , 122.Xr strerror 3 123.Sh HISTORY 124The 125.Fn psignal 126function appeared in 127.Bx 4.2 . 128