man3/sigsetops.3

   1 .\" Copyright (c) 1994 Mike Battersby
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  22 .\"
  23 .\" Modified by aeb, 960721
  24 .\" 2005-11-21, mtk, added descriptions of sigisemptyset(), sigandset(),
  25 .\"                  and sigorset()
  26 .\" 2007-10-26 mdw   added wording that a sigset_t must be initialized
  27 .\"                  prior to use
  28 .\"
  29 .TH SIGSETOPS 3 2008-09-01 "Linux" "Linux Programmer's Manual"
  30 .SH NAME
  31 sigemptyset, sigfillset, sigaddset, sigdelset, sigismember \- POSIX
  32 signal set operations.
  33 .SH SYNOPSIS
  34 .B #include <signal.h>
  35 .sp
  36 .BI "int sigemptyset(sigset_t *" set );
  37 .sp
  38 .BI "int sigfillset(sigset_t *" set );
  39 .sp
  40 .BI "int sigaddset(sigset_t *" set ", int " signum );
  41 .sp
  42 .BI "int sigdelset(sigset_t *" set ", int " signum );
  43 .sp
  44 .BI "int sigismember(const sigset_t *" set ", int " signum );
  45 .sp
  46 .in -4n
  47 Feature Test Macro Requirements for glibc (see
  48 .BR feature_test_macros (7)):
  49 .in
  50 .sp
  51 .ad l
  52 .BR sigemptyset (),
  53 .BR sigfillset (),
  54 .BR sigaddset (),
  55 .BR sigdelset (),
  56 .BR sigismember ():
  57 _POSIX_C_SOURCE\ >=\ 1 || _XOPEN_SOURCE || _POSIX_SOURCE
  58 .ad b
  59 .SH DESCRIPTION
  60 These functions allow the manipulation of POSIX signal sets.
  61 .PP
  62 .BR sigemptyset ()
  63 initializes the signal set given by
  64 .I set
  65 to empty, with all signals excluded from the set.
  66 .PP
  67 .BR sigfillset ()
  68 initializes
  69 .I set
  70 to full, including all signals.
  71 .PP
  72 .BR sigaddset ()
  73 and
  74 .BR sigdelset ()
  75 add and delete respectively signal
  76 .I signum
  77 from
  78 .IR set .
  79 .PP
  80 .BR sigismember ()
  81 tests whether
  82 .I signum
  83 is a member of
  84 .IR set .
  85 .PP
  86 Objects of type
  87 .I sigset_t
  88 must be initialized by a call to either
  89 .BR sigemptyset ()
  90 or
  91 .BR sigfillset ()
  92 before being passed to the functions
  93 .BR sigaddset (),
  94 .BR sigdelset ()
  95 and
  96 .BR sigismember ()
  97 or the additional glibc functions described below
  98 .RB ( sigisemptyset (),
  99 .BR sigandset (),
 100 and
 101 .BR sigorset ()).
 102 The results are undefined if this is not done.
 103 .SH "RETURN VALUE"
 104 .BR sigemptyset (),
 105 .BR sigfillset (),
 106 .BR sigaddset (),
 107 and
 108 .BR sigdelset ()
 109 return 0 on success and \-1 on error.
 110 .PP
 111 .BR sigismember ()
 112 returns 1 if
 113 .I signum
 114 is a member of
 115 .IR set ,
 116 0 if
 117 .I signum
 118 is not a member, and \-1 on error.
 119 .SH ERRORS
 120 .TP
 121 .B EINVAL
 122 .I sig
 123 is not a valid signal.
 124 .SH "CONFORMING TO"
 125 POSIX.1-2001.
 126 .SH NOTES
 127 .SS Glibc Notes
 128 If the
 129 .B _GNU_SOURCE
 130 feature test macro is defined, then \fI<signal.h>\fP
 131 exposes three other functions for manipulating signal
 132 sets.
 133 .TP
 134 .BI "int sigisemptyset(sigset_t *" set );
 135 returns 1 if
 136 .I set
 137 contains no signals, and 0 otherwise.
 138 .TP
 139 .BI "int sigorset(sigset_t *" dest ", sigset_t *" left \
 140 ", sigset_t *" right );
 141 places the union of the sets
 142 .I left
 143 and
 144 .I right
 145 in
 146 .IR dest .
 147 .TP
 148 .BI "int sigandset(sigset_t *" dest ", sigset_t *" left \
 149 ", sigset_t *" right );
 150 places the intersection of the sets
 151 .I left
 152 and
 153 .I right
 154 in
 155 .IR dest .
 156 .PP
 157 .BR sigorset ()
 158 and
 159 .BR sigandset ()
 160 return 0 on success, and \-1 on failure.
 161 .PP
 162 These functions are nonstandard (a few other systems provide similar
 163 functions) and their use should be avoided in portable applications.
 164 .SH "SEE ALSO"
 165 .BR sigaction (2),
 166 .BR sigpending (2),
 167 .BR sigprocmask (2),
 168 .BR sigsuspend (2)