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1.\" $NetBSD: sigsuspend.2,v 1.4 1995/02/27 12:37:46 cgd Exp $
2.\"
3.\" Copyright (c) 1983, 1991, 1993
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34.\" @(#)sigsuspend.2 8.1 (Berkeley) 6/4/93
35.\"
36.Dd June 4, 1993
37.Dt SIGSUSPEND 2
38.Os
39.Sh NAME
40.Nm sigsuspend
41.Nd atomically release blocked signals and wait for interrupt
42.Sh SYNOPSIS
43.Fd #include <signal.h>
44.Ft int
45.Fo sigsuspend
46.Fa "const sigset_t *sigmask"
47.Fc
48.Sh DESCRIPTION
49.Fn Sigsuspend
50temporarily changes the blocked signal mask to the set to which
51.Fa sigmask
52points,
53and then waits for a signal to arrive;
54on return the previous set of masked signals is restored.
55The signal mask set
56is usually empty to indicate that all
57signals are to be unblocked for the duration of the call.
58.Pp
59In normal usage, a signal is blocked using
60.Xr sigprocmask 2
61to begin a critical section, variables modified on the occurrence
62of the signal are examined to determine that there is no work
63to be done, and the process pauses awaiting work by using
64.Fn sigsuspend
65with the previous mask returned by
66.Xr sigprocmask .
67.Sh RETURN VALUES
68The
69.Fn sigsuspend
70function
71always terminates by being interrupted, returning -1 with
72.Va errno
73set to
74.Dv EINTR .
75.Sh SEE ALSO
76.Xr sigaction 2 ,
77.Xr sigprocmask 2 ,
78.Xr sigsetops 3
79.Sh STANDARDS
80The
81.Nm sigsuspend
82function call
83conforms to
84.St -p1003.1-88 .