1SIGVEC(3) Linux Programmer's Manual SIGVEC(3)
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6 sigvec, sigblock, sigsetmask, siggetmask, sigmask - BSD signal API
7
9 #include <signal.h>
10 int sigvec(int sig, struct sigvec *vec, struct sigvec *ovec);
12 int sigmask(int signum);
14 int sigblock(int mask);
16 int sigsetmask(int mask);
18 int siggetmask(void);
20 Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
22 All functions shown above: _BSD_SOURCE
24
26 These functions are provided in glibc as a compatibility interface for
27 programs that make use of the historical BSD signal API. This API is
28 obsolete: new applications should use the POSIX signal API (sigac‐
29 tion(2), sigprocmask(2), etc.)
30 The sigvec() function sets and/or gets the disposition of the signal
32 sig (like the POSIX sigaction(2)). If vec is not NULL, it points to a
33 sigvec structure that defines the new disposition for sig. If ovec is
34 not NULL, it points to a sigvec structure that is used to return the
35 previous disposition of sig. To obtain the current disposition of sig
36 without changing it, specify NULL for vec, and a non-NULL pointer for
37 ovec.
38 The dispositions for SIGKILL and SIGSTOP cannot be changed.
40 The sigvec structure has the following form:
42 struct sigvec {
44 void (*sv_handler)(); /* Signal disposition */
45 int sv_mask; /* Signals to be blocked in handler */
46 int sv_flags; /* Flags */
47 };
48 The sv_handler field specifies the disposition of the signal, and is
50 either: the address of a signal handler function; or SIG_DFL meaning
51 the default disposition applies for the signal; or SIG_IGN meaning that
52 the signal is ignored.
53 If sv_handler specifies the address of a signal handler, then sv_mask
55 specifies a mask of signals that are to be blocked while the handler is
56 executing. In addition, the signal for which the handler is invoked is
57 also blocked by default. Attempts to block SIGKILL or SIGSTOP are
58 silently ignored.
59 If sv_handler specifies the address of a signal handler, then the
61 sv_flags field specifies flags controlling what happens when the han‐
62 dler is called. This field may contain zero or more of the following
63 flags:
64 SV_INTERRUPT
66 If the signal handler interrupts a blocking system call, then
67 upon return from the handler the system call will not be
68 restarted: instead it will fail with the error EINTR. If this
69 flag is not specified, then system calls are restarted by
70 default.
71 SV_RESETHAND
73 Reset the disposition of the signal to the default before call‐
74 ing the signal handler. If this flag is not specified, then the
75 handler remains established until explicitly removed by a later
76 call to sigvec() or until the process performs an execve(2).
77 SV_ONSTACK
79 Handle the signal on the alternate signal stack (historically
80 established under BSD using the obsolete sigstack() function;
81 the POSIX replacement is sigaltstack(2)).
82 The sigmask() function constructs and returns a "signal mask" for
84 signum. For example, we can initialize the vec.sv_mask field given to
85 sigvec() using code such as the following:
86 vec.sv_mask = sigmask(SIGQUIT) | sigpause(SIGABRT);
88 /* Block SIGQUIT and SIGABRT during
89 handler execution */
90 The sigblock() function adds the signals in mask to the process's sig‐
92 nal mask (like POSIX sigprocmask(SIG_BLOCK)), and returns the process's
93 previous signal mask. Attempts to block SIGKILL or SIGSTOP are
94 silently ignored.
95 The sigsetmask() function sets the process's signal mask to the value
97 given in mask (like POSIX sigprocmask(SIG_SETMASK)), and returns the
98 process's previous signal mask.
99 The siggetmask() function returns the process's current signal mask.
101 This call is equivalent to sigblock(0).
102
104 The sigvec() function returns 0 on success; on error, it returns -1 and
105 sets errno to indicate the error.
106 The sigblock() and sigsetmask() functions return the previous signal
108 mask.
109 The sigmask() function returns the signal mask for signum.
111
113 See the ERRORS under sigaction(2) and sigprocmask(2).
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116 All of these functions were in 4.3BSD, except siggetmask(), whose ori‐
117 gin is unclear. These functions are obsolete: do not use them in new
118 programs.
119
121 On 4.3BSD, the signal() function provided reliable semantics (as when
122 calling sigvec() with vec.sv_mask equal to 0). On System V, signal()
123 provides unreliable semantics. POSIX.1-2001 leaves these aspects of
124 signal() unspecified. See signal(2) for further details.
125 In order to wait for a signal, BSD and System V both provided a func‐
127 tion named sigpause(3), but this function has a different argument on
128 the two systems. See sigpause(3) for details.
129
131 kill(2), pause(2), sigaction(2), signal(2), sigprocmask(2), raise(3),
132 sigpause(3), sigset(3), signal(7)
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135 This page is part of release 3.25 of the Linux man-pages project. A
136 description of the project, and information about reporting bugs, can
137 be found at http://www.kernel.org/doc/man-pages/.
138Linux 2007-07-26 SIGVEC(3)