man3/sigsetops.3

   1 .\" Copyright (c) 1994 Mike Battersby
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  25 .\" Modified by aeb, 960721
  26 .\" 2005-11-21, mtk, added descriptions of sigisemptyset(), sigandset(),
  27 .\"                  and sigorset()
  28 .\" 2007-10-26 mdw   added wording that a sigset_t must be initialized
  29 .\"                  prior to use
  30 .\"
  31 .TH SIGSETOPS 3 2008-09-01 "Linux" "Linux Programmer's Manual"
  32 .SH NAME
  33 sigemptyset, sigfillset, sigaddset, sigdelset, sigismember \- POSIX
  34 signal set operations.
  35 .SH SYNOPSIS
  36 .B #include <signal.h>
  37 .sp
  38 .BI "int sigemptyset(sigset_t *" set );
  39 .sp
  40 .BI "int sigfillset(sigset_t *" set );
  41 .sp
  42 .BI "int sigaddset(sigset_t *" set ", int " signum );
  43 .sp
  44 .BI "int sigdelset(sigset_t *" set ", int " signum );
  45 .sp
  46 .BI "int sigismember(const sigset_t *" set ", int " signum );
  47 .sp
  48 .in -4n
  49 Feature Test Macro Requirements for glibc (see
  50 .BR feature_test_macros (7)):
  51 .in
  52 .sp
  53 .ad l
  54 .BR sigemptyset (),
  55 .BR sigfillset (),
  56 .BR sigaddset (),
  57 .BR sigdelset (),
  58 .BR sigismember ():
  59 .RS 4
  60 _POSIX_C_SOURCE\ >=\ 1 || _XOPEN_SOURCE || _POSIX_SOURCE
  61 .RE
  62 .ad b
  63 .SH DESCRIPTION
  64 These functions allow the manipulation of POSIX signal sets.
  65 .PP
  66 .BR sigemptyset ()
  67 initializes the signal set given by
  68 .I set
  69 to empty, with all signals excluded from the set.
  70 .PP
  71 .BR sigfillset ()
  72 initializes
  73 .I set
  74 to full, including all signals.
  75 .PP
  76 .BR sigaddset ()
  77 and
  78 .BR sigdelset ()
  79 add and delete respectively signal
  80 .I signum
  81 from
  82 .IR set .
  83 .PP
  84 .BR sigismember ()
  85 tests whether
  86 .I signum
  87 is a member of
  88 .IR set .
  89 .PP
  90 Objects of type
  91 .I sigset_t
  92 must be initialized by a call to either
  93 .BR sigemptyset ()
  94 or
  95 .BR sigfillset ()
  96 before being passed to the functions
  97 .BR sigaddset (),
  98 .BR sigdelset ()
  99 and
 100 .BR sigismember ()
 101 or the additional glibc functions described below
 102 .RB ( sigisemptyset (),
 103 .BR sigandset (),
 104 and
 105 .BR sigorset ()).
 106 The results are undefined if this is not done.
 107 .SH RETURN VALUE
 108 .BR sigemptyset (),
 109 .BR sigfillset (),
 110 .BR sigaddset (),
 111 and
 112 .BR sigdelset ()
 113 return 0 on success and \-1 on error.
 114 .PP
 115 .BR sigismember ()
 116 returns 1 if
 117 .I signum
 118 is a member of
 119 .IR set ,
 120 0 if
 121 .I signum
 122 is not a member, and \-1 on error.
 123 .SH ERRORS
 124 .TP
 125 .B EINVAL
 126 .I sig
 127 is not a valid signal.
 128 .SH CONFORMING TO
 129 POSIX.1-2001.
 130 .SH NOTES
 131 .SS Glibc notes
 132 If the
 133 .B _GNU_SOURCE
 134 feature test macro is defined, then \fI<signal.h>\fP
 135 exposes three other functions for manipulating signal
 136 sets.
 137 .TP
 138 .BI "int sigisemptyset(sigset_t *" set );
 139 returns 1 if
 140 .I set
 141 contains no signals, and 0 otherwise.
 142 .TP
 143 .BI "int sigorset(sigset_t *" dest ", sigset_t *" left \
 144 ", sigset_t *" right );
 145 places the union of the sets
 146 .I left
 147 and
 148 .I right
 149 in
 150 .IR dest .
 151 .TP
 152 .BI "int sigandset(sigset_t *" dest ", sigset_t *" left \
 153 ", sigset_t *" right );
 154 places the intersection of the sets
 155 .I left
 156 and
 157 .I right
 158 in
 159 .IR dest .
 160 .PP
 161 .BR sigorset ()
 162 and
 163 .BR sigandset ()
 164 return 0 on success, and \-1 on failure.
 165 .PP
 166 These functions are nonstandard (a few other systems provide similar
 167 functions) and their use should be avoided in portable applications.
 168 .SH SEE ALSO
 169 .BR sigaction (2),
 170 .BR sigpending (2),
 171 .BR sigprocmask (2),
 172 .BR sigsuspend (2)