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.\"     @(#)psignal.3	8.2 (Berkeley) 2/27/95
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.Dd August 27, 2010
.Dt PSIGNAL 3
.Os
.Sh NAME
.Nm psignal ,
.Nm psiginfo ,
.Nm sys_siglist ,
.Nm sys_signame
.Nd system signal messages
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In signal.h
.Ft void
.Fn psignal "int sig" "const char *s"
.Fn psiginfo "const siginfo_t *si" "const char *s"
.Vt extern const char * const sys_siglist[];
.Vt extern const char * const 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
.Fn psiginfo
function produces the same output as the
.Fn psignal
function, only it uses the signal number information from the
.Fa si
argument.
.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 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 ,
.Xr setlocale 3 ,
.Xr strsignal 3
.Sh HISTORY
The
.Fn psignal
function appeared in
.Bx 4.2 .
The
.Fn psiginfo
function appeared in
.Nx 6.0 .