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.Dd $Mdocdate: May 31 2007 $
.Dt PSIGNAL 3
.Os
.Sh NAME
.Nm psignal ,
.Nm sys_siglist ,
.Nm sys_signame
.Nd system signal messages
.Sh SYNOPSIS
.Fd #include <signal.h>
.Ft void
.Fn psignal "unsigned int 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 not
.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
(see
.Xr sigaction 2
for a list),
the string
.Dq Unknown signal
is produced.
.Pp
The message strings can be accessed directly using the external array
.Va sys_siglist ,
indexed by recognized signal numbers.
The external array
.Va sys_signame
is used similarly and contains short, upper-case abbreviations for signals
which are useful for recognizing signal names in user input.
The defined value
.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 ,
.Xr setlocale 3 ,
.Xr strsignal 3
.Sh HISTORY
The
.Fn psignal
function appeared in
.Bx 4.2 .