xref: /minix3/lib/libutil/raise_default_signal.3 (revision dba3562d7800d1fed3cb2cd859754872fbb2e84f)

.\"	$NetBSD: raise_default_signal.3,v 1.3 2011/03/27 12:53:16 njoly Exp $
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.\" by Luke Mewburn.
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.Dd September 25, 2007
.Dt RAISE_DEFAULT_SIGNAL 3
.Os
.Sh NAME
.Nm raise_default_signal
.Nd raise the default signal handler
.Sh LIBRARY
.Lb libutil
.Sh SYNOPSIS
.In util.h
.Ft int
.Fo raise_default_signal
.Fa "int sig"
.Fc
.Sh DESCRIPTION
The
.Fn raise_default_signal
function raises the default signal handler for the signal
.Fa sig .
This function may be used by a user-defined signal handler router
to ensure that a parent process receives the correct notification
of a process termination by a signal.
This can be used to avoid a common programming mistake
when terminating a process from a custom
.Dv SIGINT
or
.Dv SIGQUIT
signal handler.
.Pp
The operations performed are:
.Bl -enum -offset indent
.It
Block all signals, using
.Xr sigprocmask 2 .
.It
Set the signal handler for signal
.Fa sig
to the default signal handler
.Dv ( SIG_DFL ) .
.It
.Xr raise 3
signal
.Fa sig .
.It
Unblock signal
.Fa sig
to deliver it.
.It
Restore the original signal mask and handler,
even if there was a failure.
.El
.Pp
See
.Xr signal 7
for a table of signals and default actions.
.Pp
The
.Fn raise_default_signal
function should be async-signal-safe.
.Sh RETURN VALUES
Upon successful completion, a value of 0 is returned.
Otherwise, a value of \-1 is returned and the global variable
.Va errno
is set to indicate the error.
.Sh ERRORS
The
.Fn raise_default_signal
function may fail and set
.Va errno
for any of the errors specified for the functions
.Xr sigemptyset 3 ,
.Xr sigfillset 3 ,
.Xr sigaddset 3 ,
.Xr sigprocmask 2 ,
.Xr sigaction 2 ,
or
.Xr raise 3 .
.Sh SEE ALSO
.Xr sigaction 2 ,
.Xr sigprocmask 2 ,
.Xr raise 3 ,
.Xr signal 7
.Sh HISTORY
The
.Fn raise_default_signal
function first appeared in
.Nx 5.0 .