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1 .\" $NetBSD: sigsuspend.2,v 1.4 1995/02/27 12:37:46 cgd Exp $
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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
50 temporarily changes the blocked signal mask to the set to which
51 .Fa sigmask
52 points,
53 and then waits for a signal to arrive;
54 on return the previous set of masked signals is restored.
55 The signal mask set
56 is usually empty to indicate that all
57 signals are to be unblocked for the duration of the call.
58 .Pp
59 In normal usage, a signal is blocked using
60 .Xr sigprocmask 2
61 to begin a critical section, variables modified on the occurrence
62 of the signal are examined to determine that there is no work
63 to be done, and the process pauses awaiting work by using
64 .Fn sigsuspend
65 with the previous mask returned by
66 .Xr sigprocmask .
67 .Sh RETURN VALUES
68 The
69 .Fn sigsuspend
70 function
71 always terminates by being interrupted, returning -1 with
72 .Va errno
73 set to
74 .Dv EINTR .
75 .Sh SEE ALSO
76 .Xr sigaction 2 ,
77 .Xr sigprocmask 2 ,
78 .Xr sigsetops 3
79 .Sh STANDARDS
80 The
81 .Nm sigsuspend
82 function call
83 conforms to
84 .St -p1003.1-88 .