1SIGSUSPEND(3P) POSIX Programmer's Manual SIGSUSPEND(3P)
2
6 This manual page is part of the POSIX Programmer's Manual. The Linux
7 implementation of this interface may differ (consult the corresponding
8 Linux manual page for details of Linux behavior), or the interface may
9 not be implemented on Linux.
10
12 sigsuspend — wait for a signal
13
15 #include <signal.h>
16 int sigsuspend(const sigset_t *sigmask);
18
20 The sigsuspend() function shall replace the current signal mask of the
21 calling thread with the set of signals pointed to by sigmask and then
22 suspend the thread until delivery of a signal whose action is either to
23 execute a signal-catching function or to terminate the process. This
24 shall not cause any other signals that may have been pending on the
25 process to become pending on the thread.
26 If the action is to terminate the process then sigsuspend() shall never
28 return. If the action is to execute a signal-catching function, then
29 sigsuspend() shall return after the signal-catching function returns,
30 with the signal mask restored to the set that existed prior to the sig‐
31 suspend() call.
32 It is not possible to block signals that cannot be ignored. This is
34 enforced by the system without causing an error to be indicated.
35
37 Since sigsuspend() suspends thread execution indefinitely, there is no
38 successful completion return value. If a return occurs, -1 shall be
39 returned and errno set to indicate the error.
40
42 The sigsuspend() function shall fail if:
43 EINTR A signal is caught by the calling process and control is
45 returned from the signal-catching function.
46 The following sections are informative.
48
50 None.
51
53 Normally, at the beginning of a critical code section, a specified set
54 of signals is blocked using the sigprocmask() function. When the thread
55 has completed the critical section and needs to wait for the previously
56 blocked signal(s), it pauses by calling sigsuspend() with the mask that
57 was returned by the sigprocmask() call.
58
60 Code which wants to avoid the ambiguity of the signal mask for thread
61 cancellation handlers can install an additional cancellation handler
62 which resets the signal mask to the expected value.
63 void cleanup(void *arg)
66 {
67 sigset_t *ss = (sigset_t *) arg;
68 pthread_sigmask(SIG_SETMASK, ss, NULL);
69 }
70 int call_sigsuspend(const sigset_t *mask)
72 {
73 sigset_t oldmask;
74 int result;
75 pthread_sigmask(SIG_SETMASK, NULL, &oldmask);
76 pthread_cleanup_push(cleanup, &oldmask);
77 result = sigsuspend(sigmask);
78 pthread_cleanup_pop(0);
79 return result;
80 }
81
83 None.
84
86 Section 2.4, Signal Concepts, pause(), sigaction(), sigaddset(),
87 sigdelset(), sigemptyset(), sigfillset()
88 The Base Definitions volume of POSIX.1‐2017, <signal.h>
90
92 Portions of this text are reprinted and reproduced in electronic form
93 from IEEE Std 1003.1-2017, Standard for Information Technology -- Por‐
94 table Operating System Interface (POSIX), The Open Group Base Specifi‐
95 cations Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of
96 Electrical and Electronics Engineers, Inc and The Open Group. In the
97 event of any discrepancy between this version and the original IEEE and
98 The Open Group Standard, the original IEEE and The Open Group Standard
99 is the referee document. The original Standard can be obtained online
100 at http://www.opengroup.org/unix/online.html .
101 Any typographical or formatting errors that appear in this page are
103 most likely to have been introduced during the conversion of the source
104 files to man page format. To report such errors, see https://www.ker‐
105 nel.org/doc/man-pages/reporting_bugs.html .
106IEEE/The Open Group 2017 SIGSUSPEND(3P)