sigsuspend, rt_sigsuspend - wait for a signal
#include <signal.h>
int sigsuspend(const sigset_t
*mask);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
sigsuspend(): _POSIX_C_SOURCE
sigsuspend() temporarily replaces the signal mask of
the calling thread with the mask given by mask and then
suspends the thread until delivery of a signal whose action is to invoke
a signal handler or to terminate a process.
If the signal terminates the process, then sigsuspend() does not return. If the signal is caught, then sigsuspend() returns after the signal handler returns, and the signal mask is restored to the state before the call to sigsuspend().
It is not possible to block SIGKILL or
SIGSTOP; specifying these signals in mask, has
no effect on the thread's signal mask.
sigsuspend() always returns -1, with errno
set to indicate the error (normally, EINTR).
mask points to memory which is not a valid part of the
process address space.
The call was interrupted by a signal; signal(7).
POSIX.1-2001, POSIX.1-2008.
Normally, sigsuspend() is used in conjunction with
sigprocmask(2) in order to prevent delivery of a signal
during the execution of a critical code section. The caller first blocks
the signals with sigprocmask(2). When the critical code
has completed, the caller then waits for the signals by calling
sigsuspend() with the signal mask that was returned by
sigprocmask(2) (in the oldset argument).
See sigsetops(3) for details on manipulating signal sets.
The original Linux system call was named
sigsuspend(). However, with the addition of real-time
signals in Linux 2.2, the fixed-size, 32-bit sigset_t type
supported by that system call was no longer fit for purpose.
Consequently, a new system call, rt_sigsuspend(), was
added to support an enlarged sigset_t type. The new system call
takes a second argument, size_t sigsetsize, which specifies the
size in bytes of the signal set in mask. This argument is
currently required to have the value sizeof(sigset_t) (or the
error EINVAL results). The glibc
sigsuspend() wrapper function hides these details from
us, transparently calling rt_sigsuspend() when the
kernel provides it.
kill(2), pause(2), sigaction(2), signal(2), sigprocmask(2), sigwaitinfo(2), sigsetops(3), sigwait(3), signal(7)
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