man3/sigsetops.3

   1 .\" Copyright (c) 1994 Mike Battersby
   2 .\"
   3 .\" SPDX-License-Identifier: Linux-man-pages-copyleft
   4 .\"
   5 .\" Modified by aeb, 960721
   6 .\" 2005-11-21, mtk, added descriptions of sigisemptyset(), sigandset(),
   7 .\"                  and sigorset()
   8 .\" 2007-10-26 mdw   added wording that a sigset_t must be initialized
   9 .\"                  prior to use
  10 .\"
  11 .TH SIGSETOPS 3 (date) "Linux man-pages (unreleased)"
  12 .SH NAME
  13 sigemptyset, sigfillset, sigaddset, sigdelset, sigismember \- POSIX
  14 signal set operations
  15 .SH LIBRARY
  16 Standard C library
  17 .RI ( libc ", " \-lc )
  18 .SH SYNOPSIS
  19 .nf
  20 .B #include <signal.h>
  21 .PP
  22 .BI "int sigemptyset(sigset_t *" set );
  23 .BI "int sigfillset(sigset_t *" set );
  24 .PP
  25 .BI "int sigaddset(sigset_t *" set ", int " signum );
  26 .BI "int sigdelset(sigset_t *" set ", int " signum );
  27 .PP
  28 .BI "int sigismember(const sigset_t *" set ", int " signum );
  29 .fi
  30 .PP
  31 .RS -4
  32 Feature Test Macro Requirements for glibc (see
  33 .BR feature_test_macros (7)):
  34 .RE
  35 .PP
  36 .BR sigemptyset (),
  37 .BR sigfillset (),
  38 .BR sigaddset (),
  39 .BR sigdelset (),
  40 .BR sigismember ():
  41 .nf
  42     _POSIX_C_SOURCE
  43 .fi
  44 .SH DESCRIPTION
  45 These functions allow the manipulation of POSIX signal sets.
  46 .PP
  47 .BR sigemptyset ()
  48 initializes the signal set given by
  49 .I set
  50 to empty, with all signals excluded from the set.
  51 .PP
  52 .BR sigfillset ()
  53 initializes
  54 .I set
  55 to full, including all signals.
  56 .PP
  57 .BR sigaddset ()
  58 and
  59 .BR sigdelset ()
  60 add and delete respectively signal
  61 .I signum
  62 from
  63 .IR set .
  64 .PP
  65 .BR sigismember ()
  66 tests whether
  67 .I signum
  68 is a member of
  69 .IR set .
  70 .PP
  71 Objects of type
  72 .I sigset_t
  73 must be initialized by a call to either
  74 .BR sigemptyset ()
  75 or
  76 .BR sigfillset ()
  77 before being passed to the functions
  78 .BR sigaddset (),
  79 .BR sigdelset (),
  80 and
  81 .BR sigismember ()
  82 or the additional glibc functions described below
  83 .RB ( sigisemptyset (),
  84 .BR sigandset (),
  85 and
  86 .BR sigorset ()).
  87 The results are undefined if this is not done.
  88 .SH RETURN VALUE
  89 .BR sigemptyset (),
  90 .BR sigfillset (),
  91 .BR sigaddset (),
  92 and
  93 .BR sigdelset ()
  94 return 0 on success and \-1 on error.
  95 .PP
  96 .BR sigismember ()
  97 returns 1 if
  98 .I signum
  99 is a member of
 100 .IR set ,
 101 0 if
 102 .I signum
 103 is not a member, and \-1 on error.
 104 .PP
 105 On error, these functions set
 106 .I errno
 107 to indicate the error.
 108 .SH ERRORS
 109 .TP
 110 .B EINVAL
 111 .I signum
 112 is not a valid signal.
 113 .SH ATTRIBUTES
 114 For an explanation of the terms used in this section, see
 115 .BR attributes (7).
 116 .ad l
 117 .nh
 118 .TS
 119 allbox;
 120 lbx lb lb
 121 l l l.
 122 Interface       Attribute       Value
 123 T{
 124 .BR sigemptyset (),
 125 .BR sigfillset (),
 126 .BR sigaddset (),
 127 .BR sigdelset (),
 128 .BR sigismember (),
 129 .BR sigisemptyset (),
 130 .BR sigorset (),
 131 .BR sigandset ()
 132 T}      Thread safety   MT-Safe
 133 .TE
 134 .hy
 135 .ad
 136 .sp 1
 137 .SH STANDARDS
 138 POSIX.1-2001, POSIX.1-2008.
 139 .SH NOTES
 140 When creating a filled signal set, the glibc
 141 .BR sigfillset ()
 142 function does not include the two real-time signals used internally
 143 by the NPTL threading implementation.
 144 See
 145 .BR nptl (7)
 146 for details.
 147 .\"
 148 .SS Glibc extensions
 149 If the
 150 .B _GNU_SOURCE
 151 feature test macro is defined, then \fI<signal.h>\fP
 152 exposes three other functions for manipulating signal
 153 sets:
 154 .PP
 155 .nf
 156 .BI "int sigisemptyset(const sigset_t *" set );
 157 .BI "int sigorset(sigset_t *" dest ", const sigset_t *" left ,
 158 .BI "              const sigset_t *" right );
 159 .BI "int sigandset(sigset_t *" dest ", const sigset_t *" left ,
 160 .BI "              const sigset_t *" right );
 161 .fi
 162 .PP
 163 .BR sigisemptyset ()
 164 returns 1 if
 165 .I set
 166 contains no signals, and 0 otherwise.
 167 .PP
 168 .BR sigorset ()
 169 places the union of the sets
 170 .I left
 171 and
 172 .I right
 173 in
 174 .IR dest .
 175 .BR sigandset ()
 176 places the intersection of the sets
 177 .I left
 178 and
 179 .I right
 180 in
 181 .IR dest .
 182 Both functions return 0 on success, and \-1 on failure.
 183 .PP
 184 These functions are nonstandard (a few other systems provide similar
 185 functions) and their use should be avoided in portable applications.
 186 .SH SEE ALSO
 187 .BR sigaction (2),
 188 .BR sigpending (2),
 189 .BR sigprocmask (2),
 190 .BR sigsuspend (2)