sigpause - atomically release blocked signals and wait for interrupt
Standard C library (
libc,
-lc)
#include <signal.h>
int sigpause(int sigmask); /* BSD (but see NOTES) */
int sigpause(int sig); /* System V / UNIX 95 */
Don't use this function. Use
sigsuspend(2) instead.
The function
sigpause() is designed to wait for some signal. It changes
the process's signal mask (set of blocked signals), and then waits for a
signal to arrive. Upon arrival of a signal, the original signal mask is
restored.
If
sigpause() returns, it was interrupted by a signal and the return
value is -1 with
errno set to
EINTR.
For an explanation of the terms used in this section, see
attributes(7).
Interface |
Attribute |
Value |
sigpause () |
Thread safety |
MT-Safe |
The System V version of
sigpause() is standardized in POSIX.1-2001. It is
also specified in POSIX.1-2008, where it is marked obsolete.
The classical BSD version of this function appeared in 4.2BSD. It sets the
process's signal mask to
sigmask. UNIX 95 standardized the incompatible
System V version of this function, which removes only the specified signal
sig from the process's signal mask. The unfortunate situation with two
incompatible functions with the same name was solved by the
sigsuspend(2) function, that takes a
sigset_t * argument
(instead of an
int).
On Linux, this routine is a system call only on the Sparc (sparc64)
architecture.
glibc uses the BSD version if the
_BSD_SOURCE feature test macro is
defined and none of
_POSIX_SOURCE,
_POSIX_C_SOURCE,
_XOPEN_SOURCE,
_GNU_SOURCE, or
_SVID_SOURCE is defined.
Otherwise, the System V version is used, and feature test macros must be
defined as follows to obtain the declaration:
- •
- Since glibc 2.26: _XOPEN_SOURCE >= 500
- •
- glibc 2.25 and earlier: _XOPEN_SOURCE
Since glibc 2.19, only the System V version is exposed by
<signal.h>; applications that formerly used the BSD
sigpause() should be amended to use
sigsuspend(2).
kill(2),
sigaction(2),
sigprocmask(2),
sigsuspend(2),
sigblock(3),
sigvec(3),
feature_test_macros(7)