Section: Linux Programmer's Manual (2)
sigsuspend, rt_sigsuspend - wait for a signal
int sigsuspend(const sigset_t *mask);
Feature Test Macro Requirements for glibc (see
temporarily replaces the signal mask of the calling thread with the
mask given by
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
does not return.
If the signal is caught, then
returns after the signal handler returns,
and the signal mask is restored to the state before the call to
It is not possible to block
specifying these signals in
has no effect on the thread's signal mask.
always returns -1, with
set to indicate the error (normally,
points to memory which is not a valid part of the process address space.
The call was interrupted by a signal;
is used in conjunction with
in order to prevent delivery of a signal during the execution of a
critical code section.
The caller first blocks the signals with
When the critical code has completed, the caller then waits for the
signals by calling
with the signal mask that was returned by
for details on manipulating signal sets.
C library/kernel differences
The original Linux system call was named
However, with the addition of real-time signals in Linux 2.2,
the fixed-size, 32-bit
type supported by that system call was no longer fit for purpose.
Consequently, a new system call,
was added to support an enlarged
The new system call takes a second argument,
which specifies the size in bytes of the signal set in
This argument is currently required to have the value
(or the error
wrapper function hides these details from us, transparently calling
when the kernel provides it.
This page is part of release 5.10 of the Linux
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