.TH sigemptyset() "" "" "Signal Function (libc)"
.PC "Initialize a set of signals"
.B "#include <signal.h>"
\fBint sigemptyset (\fIset\^\fB)\fR
\fBsigset_t *\fIset\^\fB;\fR
.PP
.B sigemptyset()
is one of a set of signalling functions that manipulate
data objects addressable by the application, instead of a
set of signals known to the system.
It initializes the set of signals to which
.I set
points, such that all standard signals are excluded.
.PP
.B sigemptyset()
returns zero if all goes well.
If a problem occurs, it returns \-1 and sets
.B errno
to an appropriate value.
.PP
An application must call either
.B sigemptyset()
or
.B sigfillset()
at least once for each object of type
.B sigset_t
prior to any other object.
If such an object is not initialized in this way,
but is supplied as an argument to any of the functions
.BR sigaddset() ,
.BR sigdelset() ,
.BR sigismember() ,
.BR sigaction() ,
.BR sigprocmask() ,
.BR sigpending() ,
or
.BR sigsuspend() ,
the results are undefined.
.SH "See Also"
.Xr "libc," libc
.Xr "sigaction()," sigaction
.Xr "sigaddset()," sigaddset
.Xr "sigdelset()," sigdelset
.Xr "sigfillset()," sigfillse
.Xr "sigismember()" sigismemb
.SH Notes
If your program is compiled using the System V Release 4 compilation
environment, this is a function that is linked in from
.BR libc .
If not, a macro form is used.
