signal.c File Reference

Detailed Description

Signal handling functions.

Functions
int	signal_init (void)
void	para_sigaction (int sig, void(*handler)(int))
void	para_install_sighandler (int sig)
void	para_block_signal (int sig)
void	para_unblock_signal (int sig)
int	para_next_signal (void)

Function Documentation

signal_init()

int signal_init

(

void

)

Initialize the paraslash signal subsystem.

This function creates the signal pipe to deliver pending signals to the application (Bernstein's trick). It is usually called at startup, followed by subsequent calls to para_install_sighandler() for each signal that should be caught.

The same generic signal handler is installed for all signals. When a signal arrives, the handler writes the signal number to the write end of the pipe. By checking the read end the application can tell which signal, if any, has arrived.

Returns

This function either succeeds or calls exit(3) to terminate the current process. On success, the function returns the descriptor of the read end of the pipe.

para_sigaction()

void para_sigaction	(	int	sig,
		void(*)(int)	handler
	)

Install the given handler for the given signal.

Parameters

sig	The number of the signal to catch.
handler	to be installed, SIG_IGN, or SIG_DFL.

This either succeeds or calls exit(EXIT_FAILURE).

See also

sigaction(2).

Referenced by para_install_sighandler().

para_install_sighandler()

void para_install_sighandler

(

int

sig

)

Install the generic signal handler for the given signal number.

Parameters

sig	The number of the signal to catch.

See also

signal(2), sigaction(2).

para_block_signal()

void para_block_signal

(

int

sig

)

Block a signal for the caller.

Parameters

sig	The signal to block.

This sets the given signal in the current signal mask of the calling process to prevent this signal from delivery.

See also

para_unblock_signal(), sigprocmask(2), sigaddset(3).

para_unblock_signal()

void para_unblock_signal

(

int

sig

)

Unblock a signal.

Parameters

sig	The signal to unblock.

This function removes the given signal from the current set of blocked signals.

See also

para_block_signal(), sigprocmask(2), sigaddset(3).

para_next_signal()

int para_next_signal

(

void

)

Return the number of the next pending signal.

Returns

On success, the number of the received signal is returned. If there is no signal currently pending, the function returns zero. On read errors from the signal pipe, the process is terminated.