NAME
sigpause — signal management
SYNOPSIS
#include <signal.h>
int sigpause(int sig);
Obsolescent
long sigpause(long mask);
DESCRIPTION
The
sigpause()
function, along with the
sighold(),
sigignore(),
sigrelse(),
and
sigset()
functions provide simplified signal management.
The
sigpause()
function removes
sig
from the calling thread's signal mask and suspends
the calling thread until a signal is received. The
sigpause()
function restores the thread's signal mask to its
original state before returning.
RETURN VALUE
The
sigpause()
function suspends execution of the thread until a
signal is received, whereupon it shall return
-1
and set
errno
to
EINTR.
ERRORS
- [EINVAL]
sig
is not a valid signal number.
WARNINGS
The
_XPG4_EXTENDED
compiler option must be set to use
sigpause().
The use of the function without the option is unspecified.
sigpause()
should not be used in conjunction with
signal(2)
and
sigspace(2).
OBSOLESCENT FUNCTION
sigpause(long)
will be obsoleted in the near future.
The obsolescent
sigpause()
function
blocks signals according to the value of
mask,
then atomically waits for an unmasked signal to arrive.
On return,
sigpause()
restores the current signal mask to the value that existed before the
sigpause()
call.
When no signals are to be blocked, a value of
0L
is used for
mask.
sigpause()
terminates when it is interrupted by a signal.
When
sigpause()
terminates, it returns -l and sets
errno
to
EINTR.
The obsolescent
sigpause()
function is typically used in conjunction with the obsoleted
sigblock()
function.
Threads Considerations
Since blocked signal masks are maintained at the thread level,
the obsolescent
sigpause()
function
modifies only the calling thread's blocked signal mask.
sigpause()
suspends only the calling thread until it receives a signal.
If other threads in the process do not block the signal, the
signal may be delivered to another thread in the process and the
thread in
sigpause()
may continue waiting. For this reason, the use of
sigwait(2)
is recommended instead of
sigpause()
for multi-threaded applications.
For more information regarding signals and threads, refer to
signal(5).
LP64 Programs
This obsolescent
sigpause()
accepts a long (64 bit) value. However, as for ILP32 programs,
sigpause()
supports signals numbered 1 through 32. The upper 32 bits of the mask
argument are ignored.
Author
sigpause(long)
was developed by the University of California, Berkeley.
SEE ALSO
kill(1),
kill(2),
pause(2),
signal(2),
wait(2),
abort(3C),
setjmp(3C),
sighold(3C),
sigignore(3C),
sigrelse(3C),
sigset(3C),
signal(5).
STANDARDS CONFORMANCE
sigpause(): SVID2, SVID3
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