man3/sigwait.3

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  26 .TH SIGWAIT 3 2017-07-13 "Linux" "Linux Programmer's Manual"
  27 .SH NAME
  28 sigwait \- wait for a signal
  29 .SH SYNOPSIS
  30 .nf
  31 .B #include <signal.h>
  32 .PP
  33 .BI " int sigwait(const sigset_t *" set ", int *" sig );
  34 .fi
  35 .PP
  36 .in -4n
  37 Feature Test Macro Requirements for glibc (see
  38 .BR feature_test_macros (7)):
  39 .in
  40 .PP
  41 .ad l
  42 .BR sigwait ():
  43 .RS 4
  44 Since glibc 2.26:
  45     _POSIX_C_SOURCE >= 199506L
  46 .br
  47 Glibc 2.25 and earlier:
  48     _POSIX_C_SOURCE
  49 .RE
  50 .ad b
  51 .SH DESCRIPTION
  52 The
  53 .BR sigwait ()
  54 function suspends execution of the calling thread until
  55 one of the signals specified in the signal set
  56 .IR set
  57 becomes pending.
  58 The function accepts the signal
  59 (removes it from the pending list of signals),
  60 and returns the signal number in
  61 .IR sig .
  62 .PP
  63 The operation of
  64 .BR sigwait ()
  65 is the same as
  66 .BR sigwaitinfo (2),
  67 except that:
  68 .IP * 2
  69 .BR sigwait ()
  70 returns only the signal number, rather than a
  71 .I siginfo_t
  72 structure describing the signal.
  73 .IP *
  74 The return values of the two functions are different.
  75 .SH RETURN VALUE
  76 On success,
  77 .BR sigwait ()
  78 returns 0.
  79 On error, it returns a positive error number (listed in ERRORS).
  80 .SH ERRORS
  81 .TP
  82 .B EINVAL
  83 .\" Does not occur for glibc.
  84 .I set
  85 contains an invalid signal number.
  86 .SH ATTRIBUTES
  87 For an explanation of the terms used in this section, see
  88 .BR attributes (7).
  89 .TS
  90 allbox;
  91 lb lb lb
  92 l l l.
  93 Interface       Attribute       Value
  94 T{
  95 .BR sigwait ()
  96 T}      Thread safety   MT-Safe
  97 .TE
  98 .SH CONFORMING TO
  99 POSIX.1-2001, POSIX.1-2008.
 100 .SH NOTES
 101 .BR sigwait ()
 102 is implemented using
 103 .BR sigtimedwait (2).
 104 .PP
 105 The glibc implementation of
 106 .BR sigwait ()
 107 silently ignores attempts to wait for the two real-time signals that
 108 are used internally by the NPTL threading implementation.
 109 See
 110 .BR nptl (7)
 111 for details.
 112 .SH EXAMPLES
 113 See
 114 .BR pthread_sigmask (3).
 115 .SH SEE ALSO
 116 .BR sigaction (2),
 117 .BR signalfd (2),
 118 .BR sigpending (2),
 119 .BR sigsuspend (2),
 120 .BR sigwaitinfo (2),
 121 .BR sigsetops (3),
 122 .BR signal (7)