.\" Copyright (c) 1983, 1991 Regents of the University of California.
.\" All rights reserved.
.\"
.\" %sccs.include.redist.man%
.\"
.\"     @(#)psignal.3	6.4 (Berkeley) 03/02/93
.\"
.Dd 
.Dt PSIGNAL 3
.Os BSD 4.2
.Sh NAME
.Nm psignal ,
.Nm sys_siglist
.Nm sys_signame
.Nd system signal messages
.Sh SYNOPSIS
.Fd #include <sys/signal.h>
.Ft void
.Fn psignal "unsigned sig" "const char *s"
.Vt extern char *sys_siglist[];
.Vt extern char *sys_signame[];
.Sh DESCRIPTION
The
.Fn psignal
function locates the descriptive message
string for the given signal number
.Fa sig
and writes it to the standard error.
.Pp
If the argument
.Fa s
is
.Pf non- Dv NULL
it is written to the standard error file descriptor
prior to the message string,
immediately followed by a colon and a space.
If the signal number is not recognized
.Pq Xr sigaction 2 ,
the string
.Dq "Unknown signal
is produced.
.Pp
The message strings can be accessed directly
through the external array
.Va sys_siglist ,
indexed by recognized signal numbers.
The external array
.Va sys_signame
is used similarly and
contains short, lower-case abbreviations for signals
which are useful for recognizing signal names
in user input.
The defined variable
.Dv NSIG
contains a count of the strings in
.Va sys_siglist
and
.Va sys_signame .
.Sh SEE ALSO
.Xr sigaction 2 ,
.Xr perror 3
.Sh HISTORY
The
.Fn psignal
function appeared in 
.Bx 4.2 .