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.\" 35.Dd February 27, 1995 36.Dt PSIGNAL 3 37.Os 38.Sh NAME 39.Nm psignal , 40.Nm strsignal , 41.Nm sys_siglist , 42.Nm sys_signame , 43.Nm sys_nsig 44.Nd system signal messages 45.Sh LIBRARY 46.Lb libc 47.Sh SYNOPSIS 48.In signal.h 49.Ft void 50.Fn psignal "unsigned sig" "const char *s" 51.Vt extern const char * const sys_siglist[] ; 52.Vt extern const char * const sys_signame[] ; 53.Vt extern const int sys_nsig ; 54.In string.h 55.Ft "char *" 56.Fn strsignal "int sig" 57.Sh DESCRIPTION 58The 59.Fn psignal 60and 61.Fn strsignal 62functions locate the descriptive message 63string for a signal number. 64.Pp 65The 66.Fn strsignal 67function accepts a signal number argument 68.Fa sig 69and returns a pointer to the corresponding message string. 70.Pp 71The 72.Fn psignal 73function accepts a signal number argument 74.Fa sig 75and writes it to the standard error. 76If the argument 77.Fa s 78is 79.Pf non- Dv NULL 80and does not point to the null character, 81.Fa s 82is written to the standard error file descriptor 83prior to the message string, 84immediately followed by a colon and a space. 85If the signal number is not recognized 86.Pq Xr sigaction 2 , 87the string 88.Dq "Unknown signal" 89is produced. 90.Pp 91The message strings can be accessed directly 92through the external array 93.Va sys_siglist , 94indexed by recognized signal numbers. 95The external array 96.Va sys_signame 97is used similarly and 98contains short, lower-case abbreviations for signals 99which are useful for recognizing signal names 100in user input. 101The external variable 102.Va sys_nsig 103contains a count of the strings in 104.Va sys_siglist 105and 106.Va sys_signame . 107Note that the defined variable 108.Dv NSIG 109will typically be the same as 110.Va sys_nsig , 111but might be different due to newer or older kernels and newer or 112older libc libraries. For maximum portability you must use 113.Va sys_nsig 114to limit-check the above arrays. Additionally, you should check 115for 116.Dv NULL 117array entries and generate a generic signal name in those cases. 118.Sh SEE ALSO 119.Xr sigaction 2 , 120.Xr perror 3 , 121.Xr strerror 3 122.Sh HISTORY 123The 124.Fn psignal 125function appeared in 126.Bx 4.2 . 127