sys/sigwait.2

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  28 .\" $FreeBSD: src/lib/libc_r/man/sigwait.3,v 1.7 2001/10/01 16:09:09 ru Exp $
  29 .Dd April 27, 2000
  30 .Dt SIGWAIT 2
  31 .Os
  32 .Sh NAME
  33 .Nm sigwait
  34 .Nd select a set of signals
  35 .Sh SYNOPSIS
  36 .In signal.h
  37 .Ft int
  38 .Fn sigwait "const sigset_t *restrict set" "int *restrict sig"
  39 .Sh DESCRIPTION
  40 The
  41 .Fn sigwait
  42 function selects a set of signals, specified by
  43 .Fa set .
  44 If none of the selected signals are pending,
  45 .Fn sigwait
  46 waits until one or more of the selected signals has been generated.
  47 Then
  48 .Fn sigwait
  49 atomically clears one of the selected signals from the set of pending signals
  50 for the process and sets the location pointed to by
  51 .Fa sig
  52 to the signal number that was cleared.
  53 .Pp
  54 The signals specified by
  55 .Fa set
  56 should be blocked, but not ignored, at the time of the call to
  57 .Fn sigwait .
  58 .Pp
  59 Processes which call
  60 .Fn sigwait
  61 on ignored signals will wait indefinitely.  Ignored
  62 signals are dropped immediately by the system, before delivery
  63 to a waiting process.
  64 .Sh RETURN VALUES
  65 If successful,
  66 .Fn sigwait
  67 returns 0 and sets the location pointed to by
  68 .Fa sig
  69 to the cleared signal number.
  70 Otherwise, an error number is returned.
  71 .Sh ERRORS
  72 .Fn sigwait
  73 will fail if:
  74 .Bl -tag -width Er
  75 .It Bq Er EINVAL
  76 .Fa set
  77 specifies one or more invalid signal numbers.
  78 .El
  79 .Sh SEE ALSO
  80 .Xr pthread_sigmask 2 ,
  81 .Xr sigaction 2 ,
  82 .Xr sigpending 2 ,
  83 .Xr sigsuspend 2 ,
  84 .Xr pause 3
  85 .Sh STANDARDS
  86 .Fn sigwait
  87 conforms to ISO/IEC 9945-1:1996 (``POSIX.1'')