POSIX Signals option group. More...

Data Structures
struct	sigset_t
	Set of signals (bitmask). More...

Functions
int	kill (pid_t pid, int sig)
	Send a signal to a process or process group.

int	sigaction (int sig, const struct sigaction ZRESTRICT act, struct sigaction ZRESTRICT oact)
	Examine and change a signal action.

int	sigaddset (sigset_t *set, int sig)
	Add a signal to a signal set.

int	sigdelset (sigset_t *set, int sig)
	Delete a signal from a signal set.

int	sigemptyset (sigset_t *set)
	Initialise a signal set to the empty set.

int	sigfillset (sigset_t *set)
	Initialise a signal set to the full set (all signals).

int	sighold (int sig)
	Add a signal to the calling process's signal mask (XSI, obsolescent).

int	sigignore (int sig)
	Set a signal's disposition to SIG_IGN (XSI, obsolescent).

int	siginterrupt (int sig, int flag)
	Control whether a signal restarts or interrupts system calls (XSI, obsolescent).

int	sigismember (const sigset_t *set, int sig)
	Test whether a signal is a member of a signal set.

int	sigpause (int sig)
	Suspend execution until a signal is delivered (XSI, obsolescent).

int	sigpending (sigset_t *set)
	Retrieve the set of pending signals.

int	sigprocmask (int how, const sigset_t ZRESTRICT set, sigset_t ZRESTRICT oset)
	Examine and change the calling process's signal mask.

int	sigrelse (int sig)
	Remove a signal from the process signal mask (XSI, obsolescent).

sighandler_t	sigset (int sig, sighandler_t disp)
	Set the disposition of a signal, optionally blocking it first (XSI, obsolescent).

int	sigsuspend (const sigset_t *set)
	Wait for a signal, atomically replacing the process signal mask.

int	sigwait (const sigset_t ZRESTRICT set, int ZRESTRICT sig)
	Wait for a signal from a set.

unsigned int	alarm (unsigned int seconds)
	Schedule an alarm signal (SIGALRM) after a given number of seconds.

int	pause (void)
	Suspend process execution until a signal is received.

Detailed Description

POSIX Signals option group.

Covers alarm(), pause(), kill(), sigaction(), sigprocmask(), sigsuspend(), sigpending(), and related signal-handling functions.

Function Documentation

◆ alarm()

unsigned int alarm ( unsigned int seconds )

Schedule an alarm signal (SIGALRM) after a given number of seconds.

◆ kill()

int kill	(	pid_t	pid,
		int	sig
	)

Send a signal to a process or process group.

Parameters

pid	Target process ID (positive), process group (negative), or 0.
sig	Signal number, or 0 to check process existence.

Returns: 0 on success, or -1 with errno set on failure.

See also: https://pubs.opengroup.org/onlinepubs/9699919799/functions/kill.html

◆ pause()

int pause ( void )

Suspend process execution until a signal is received.

See also: https://pubs.opengroup.org/onlinepubs/9699919799/functions/pause.html

◆ sigaction()

int sigaction	(	int	sig,
		const struct sigaction *ZRESTRICT	act,
		struct sigaction *ZRESTRICT	oact
	)

Examine and change a signal action.

Parameters

sig	Signal number.
act	New action, or NULL to query.
oact	Output: previous action, or NULL.

Returns: 0 on success, or -1 with errno set on failure.

See also: https://pubs.opengroup.org/onlinepubs/9699919799/functions/sigaction.html

◆ sigaddset()

int sigaddset	(	sigset_t *	set,
		int	sig
	)

Add a signal to a signal set.

Parameters

set	Signal set.
sig	Signal number to add.

Returns: 0 on success, or -1 with errno set on failure.

See also: https://pubs.opengroup.org/onlinepubs/9699919799/functions/sigaddset.html

◆ sigdelset()

int sigdelset	(	sigset_t *	set,
		int	sig
	)

Delete a signal from a signal set.

Parameters

set	Signal set.
sig	Signal number to remove.

Returns: 0 on success, or -1 with errno set on failure.

See also: https://pubs.opengroup.org/onlinepubs/9699919799/functions/sigdelset.html

◆ sigemptyset()

int sigemptyset ( sigset_t * set )

Initialise a signal set to the empty set.

Parameters

set	Signal set to clear.

Returns: 0 on success, or -1 with errno set on failure.

See also: https://pubs.opengroup.org/onlinepubs/9699919799/functions/sigemptyset.html

◆ sigfillset()

int sigfillset ( sigset_t * set )

Initialise a signal set to the full set (all signals).

Parameters

set	Signal set to fill.

Returns: 0 on success, or -1 with errno set on failure.

See also: https://pubs.opengroup.org/onlinepubs/9699919799/functions/sigfillset.html

◆ sighold()

int sighold ( int sig )

Add a signal to the calling process's signal mask (XSI, obsolescent).

Parameters

sig	Signal to block.

Returns: 0 on success, or -1 with errno set on failure.

See also: https://pubs.opengroup.org/onlinepubs/9699919799/functions/sighold.html

◆ sigignore()

int sigignore ( int sig )

Set a signal's disposition to SIG_IGN (XSI, obsolescent).

Parameters

sig	Signal to ignore.

Returns: 0 on success, or -1 with errno set on failure.

See also: https://pubs.opengroup.org/onlinepubs/9699919799/functions/sigignore.html

◆ siginterrupt()

int siginterrupt	(	int	sig,
		int	flag
	)

Control whether a signal restarts or interrupts system calls (XSI, obsolescent).

Parameters

sig	Signal number.
flag	Non-zero to interrupt; 0 to restart.

Returns: 0 on success, or -1 with errno set on failure.

See also: https://pubs.opengroup.org/onlinepubs/9699919799/functions/siginterrupt.html

◆ sigismember()

int sigismember	(	const sigset_t *	set,
		int	sig
	)

Test whether a signal is a member of a signal set.

Parameters

set	Signal set to query.
sig	Signal number to test.

Returns: 1 if the signal is a member, 0 if not, or -1 with errno set on failure.

See also: https://pubs.opengroup.org/onlinepubs/9699919799/functions/sigismember.html

◆ sigpause()

int sigpause ( int sig )

Suspend execution until a signal is delivered (XSI, obsolescent).

Parameters

sig	Signal whose blocking is temporarily removed.

Returns: Always returns -1 with errno set to EINTR.

See also: https://pubs.opengroup.org/onlinepubs/9699919799/functions/sigpause.html

◆ sigpending()

int sigpending ( sigset_t * set )

Retrieve the set of pending signals.

Parameters

set	Output: set of signals pending delivery to the calling process.

Returns: 0 on success, or -1 with errno set on failure.

See also: https://pubs.opengroup.org/onlinepubs/9699919799/functions/sigpending.html

◆ sigprocmask()

int sigprocmask	(	int	how,
		const sigset_t *ZRESTRICT	set,
		sigset_t *ZRESTRICT	oset
	)

Examine and change the calling process's signal mask.

Parameters

how	`SIG_BLOCK`, `SIG_UNBLOCK`, or `SIG_SETMASK`.
set	Signal set to apply, or NULL.
oset	Output: previous mask, or NULL.

Returns: 0 on success, or -1 with errno set on failure.

See also: https://pubs.opengroup.org/onlinepubs/9699919799/functions/sigprocmask.html

◆ sigrelse()

int sigrelse ( int sig )

Remove a signal from the process signal mask (XSI, obsolescent).

Parameters

sig	Signal to unblock.

Returns: 0 on success, or -1 with errno set on failure.

See also: https://pubs.opengroup.org/onlinepubs/9699919799/functions/sigrelse.html

◆ sigset()

sighandler_t sigset	(	int	sig,
		sighandler_t	disp
	)

Set the disposition of a signal, optionally blocking it first (XSI, obsolescent).

Parameters

sig	Signal number.
disp	New disposition (SIG_DFL, SIG_IGN, SIG_HOLD, or a handler).

Returns: Previous disposition on success, or SIG_ERR on failure.

See also: https://pubs.opengroup.org/onlinepubs/9699919799/functions/sigset.html

◆ sigsuspend()

int sigsuspend ( const sigset_t * set )

Wait for a signal, atomically replacing the process signal mask.

Parameters

set	New signal mask to apply while waiting.

Returns: Always returns -1 with errno set to EINTR.

See also: https://pubs.opengroup.org/onlinepubs/9699919799/functions/sigsuspend.html

◆ sigwait()

int sigwait	(	const sigset_t *ZRESTRICT	set,
		int *ZRESTRICT	sig
	)

Wait for a signal from a set.

Parameters

set	Output signal set to wait on.
sig	Output: number of the accepted signal.

Returns: 0 on success, or a positive error number on failure.

See also: https://pubs.opengroup.org/onlinepubs/9699919799/functions/sigwait.html

Data Structures

Functions

Detailed Description

Function Documentation

◆ alarm()

◆ kill()

◆ pause()

◆ sigaction()

◆ sigaddset()

◆ sigdelset()

◆ sigemptyset()

◆ sigfillset()

◆ sighold()

◆ sigignore()

◆ siginterrupt()

◆ sigismember()

◆ sigpause()

◆ sigpending()

◆ sigprocmask()

◆ sigrelse()

◆ sigset()

◆ sigsuspend()

◆ sigwait()