— select a set of
Standard C Library (libc, -lc)
sigset_t * restrict set
int * restrict sig
() system call selects a set of signals, specified
. If none of the selected signals are pending,
() waits until one or more of the selected signals
has been generated. Then sigwait
() atomically clears one of
the selected signals from the set of pending signals for the process and sets
the location pointed to by sig
to the signal number that
The signals specified by set
should be blocked at the time
of the call to sigwait
If more than one thread is using sigwait
() to wait for the
same signal, no more than one of these threads will return from
() with the signal number. If more than a single
thread is blocked in sigwait
() for a signal when that signal
is generated for the process, it is unspecified which of the waiting threads
returns from sigwait
(). If the signal is generated for a
specific thread, as by pthread_kill
(), only that thread will
Should any of the multiple pending signals in the range
selected, it will be the lowest numbered one. The selection order between
realtime and non-realtime signals, or between multiple pending non-realtime
signals, is unspecified.
If successful, sigwait
() returns 0 and sets the location
pointed to by sig
to the cleared signal number.
Otherwise, an error number is returned.
() system call will fail if:
- The set argument specifies one or
more invalid signal numbers.
- Any arguments point outside the allocated address space or
there is a memory protection fault.
() function conforms to ISO/IEC