1 .\" Copyright (c) 2002 Michael Kerrisk <mtk.manpages@gmail.com>
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23 .TH SIGWAITINFO 2 2012-05-02 "Linux" "Linux Programmer's Manual"
25 sigwaitinfo, sigtimedwait \- synchronously wait for queued signals
28 .B #include <signal.h>
30 .BI "int sigwaitinfo(const sigset_t *" set ", siginfo_t *" info ");"
32 .BI "int sigtimedwait(const sigset_t *" set ", siginfo_t *" info ", "
33 .BI " const struct timespec *" timeout ");"
37 Feature Test Macro Requirements for glibc (see
38 .BR feature_test_macros (7)):
43 _POSIX_C_SOURCE\ >=\ 199309L
46 suspends execution of the calling thread until one of the signals in
49 (If one of the signals in
51 is already pending for the calling thread,
53 will return immediately with information about that signal.)
56 removes the delivered signal from the set of pending
57 signals and returns the signal number as its function result.
61 then it returns a structure of type
65 containing information about the signal.
69 are delivered in the usual order; see
74 operates in exactly the same way as
76 except that it has an additional argument,
78 which specifies a minimum interval for which
79 the thread is suspended waiting for a signal.
80 (This interval will be rounded up to the system clock granularity,
81 and kernel scheduling delays mean that the interval
82 may overrun by a small amount.)
83 This argument is of the following type:
88 long tv_sec; /* seconds */
89 long tv_nsec; /* nanoseconds */
94 If both fields of this structure are specified as 0, a poll is performed:
96 returns immediately, either with information about a signal that
97 was pending for the caller, or with an error
98 if none of the signals in
106 return a signal number (i.e., a value greater than zero).
107 On failure both calls return \-1, with
109 set to indicate the error.
115 was delivered within the
121 The wait was interrupted by a signal handler; see
123 (This handler was for a signal other than one of those in
132 In normal usage, the calling program blocks the signals in
136 (so that the default disposition for these signals does not occur if they
137 are delivered between successive calls to
141 and does not establish handlers for these signals.
142 In a multithreaded program,
143 the signal should be blocked in all threads to prevent
144 the signal being delivered to a thread other than the one calling
147 .BR sigtimedwait ()).
149 The set of signals that is pending for a given thread is the
150 union of the set of signals that is pending specifically for that thread
151 and the set of signals that is pending for the process as a whole (see
158 are silently ignored.
160 If multiple threads of a process are blocked
161 waiting for the same signal(s) in
165 then exactly one of the threads will actually receive the
166 signal if it is delivered to the process as a whole;
167 which of the threads receives the signal is indeterminate.
169 POSIX leaves the meaning of a NULL value for the
173 unspecified, permitting the possibility that this has the same meaning
176 and indeed this is what is done on Linux.
180 is a library function implemented on top of