2 .\" Copyright (c) 2005 by Michael Kerrisk <mtk.manpages@gmail.com>
4 .\" %%%LICENSE_START(VERBATIM)
5 .\" Permission is granted to make and distribute verbatim copies of this
6 .\" manual provided the copyright notice and this permission notice are
7 .\" preserved on all copies.
9 .\" Permission is granted to copy and distribute modified versions of this
10 .\" manual under the conditions for verbatim copying, provided that the
11 .\" entire resulting derived work is distributed under the terms of a
12 .\" permission notice identical to this one.
14 .\" Since the Linux kernel and libraries are constantly changing, this
15 .\" manual page may be incorrect or out-of-date. The author(s) assume no
16 .\" responsibility for errors or omissions, or for damages resulting from
17 .\" the use of the information contained herein. The author(s) may not
18 .\" have taken the same level of care in the production of this manual,
19 .\" which is licensed free of charge, as they might when working
22 .\" Formatted or processed versions of this manual, if unaccompanied by
23 .\" the source, must acknowledge the copyright and authors of this work.
26 .TH SIGVEC 3 2017-09-15 "Linux" "Linux Programmer's Manual"
28 sigvec, sigblock, sigsetmask, siggetmask, sigmask \- BSD signal API
30 .B #include <signal.h>
32 .BI "int sigvec(int " sig ", const struct sigvec *" vec ", struct sigvec *" ovec );
34 .BI "int sigmask(int " signum );
36 .BI "int sigblock(int " mask );
38 .BI "int sigsetmask(int " mask );
40 .B int siggetmask(void);
43 Feature Test Macro Requirements for glibc (see
44 .BR feature_test_macros (7)):
47 All functions shown above:
50 Glibc 2.19 and earlier:
53 These functions are provided in glibc as a compatibility interface
54 for programs that make use of the historical BSD signal API.
55 This API is obsolete: new applications should use the POSIX signal API
62 function sets and/or gets the disposition of the signal
68 is not NULL, it points to a
70 structure that defines the new disposition for
74 is not NULL, it points to a
76 structure that is used to return the previous disposition of
78 To obtain the current disposition of
80 without changing it, specify NULL for
82 and a non-null pointer for
93 structure has the following form:
98 void (*sv_handler)(int); /* Signal disposition */
99 int sv_mask; /* Signals to be blocked in handler */
100 int sv_flags; /* Flags */
107 field specifies the disposition of the signal, and is either:
108 the address of a signal handler function;
110 meaning the default disposition applies for the signal; or
112 meaning that the signal is ignored.
116 specifies the address of a signal handler, then
118 specifies a mask of signals that are to be blocked while
119 the handler is executing.
120 In addition, the signal for which the handler is invoked is
126 are silently ignored.
130 specifies the address of a signal handler, then the
132 field specifies flags controlling what happens when the handler is called.
133 This field may contain zero or more of the following flags:
136 If the signal handler interrupts a blocking system call,
137 then upon return from the handler the system call s not be restarted:
138 instead it fails with the error
140 If this flag is not specified, then system calls are restarted
144 Reset the disposition of the signal to the default
145 before calling the signal handler.
146 If this flag is not specified, then the handler remains established
147 until explicitly removed by a later call to
149 or until the process performs an
153 Handle the signal on the alternate signal stack
154 (historically established under BSD using the obsolete
156 function; the POSIX replacement is
157 .BR sigaltstack (2)).
161 macro constructs and returns a "signal mask" for
163 For example, we can initialize the
167 using code such as the following:
171 vec.sv_mask = sigmask(SIGQUIT) | sigmask(SIGABRT);
172 /* Block SIGQUIT and SIGABRT during
179 function adds the signals in
181 to the process's signal mask
183 .IR sigprocmask(SIG_BLOCK) ),
184 and returns the process's previous signal mask.
189 are silently ignored.
193 function sets the process's signal mask to the value given in
196 .IR sigprocmask(SIG_SETMASK) ),
197 and returns the process's previous signal mask.
201 function returns the process's current signal mask.
202 This call is equivalent to
207 function returns 0 on success; on error, it returns \-1 and sets
209 to indicate the error.
215 functions return the previous signal mask.
219 macro returns the signal mask for
227 Starting with version 2.21, the GNU C library no longer exports the
229 function as part of the ABI.
230 (To ensure backward compatibility,
231 the glibc symbol versioning scheme continues to export the interface
232 to binaries linked against older versions of the library.)
234 For an explanation of the terms used in this section, see
240 Interface Attribute Value
247 T} Thread safety MT-Safe
250 All of these functions were in
253 whose origin is unclear.
254 These functions are obsolete: do not use them in new programs.
258 function provided reliable semantics (as when calling
265 provides unreliable semantics.
266 POSIX.1 leaves these aspects of
273 In order to wait for a signal,
274 BSD and System V both provided a function named
276 but this function has a different argument on the two systems.