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