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SIGINTERRUPT(3)	       FreeBSD Library Functions Manual	       SIGINTERRUPT(3)

NAME
     siginterrupt -- allow signals to interrupt	system calls

LIBRARY
     Standard C	Library	(libc, -lc)

SYNOPSIS
     #include <signal.h>

     int
     siginterrupt(int sig, int flag);

DESCRIPTION
     The siginterrupt()	function is used to change the system call restart
     behavior when a system call is interrupted	by the specified signal.  If
     the flag is false (0), then system	calls will be restarted	if they	are
     interrupted by the	specified signal and no	data has been transferred yet.
     System call restart has been the default behavior since 4.2BSD, and is
     the default behaviour for signal(3) on FreeBSD.

     If	the flag is true (1), then restarting of system	calls is disabled.  If
     a system call is interrupted by the specified signal and no data has been
     transferred, the system call will return -1 with the global variable
     errno set to EINTR.  Interrupted system calls that	have started transfer-
     ring data will return the amount of data actually transferred.  System
     call interrupt is the signal behavior found on 4.1BSD and AT&T System V
     UNIX systems.

     Note that the new 4.2BSD signal handling semantics	are not	altered	in any
     other way.	 Most notably, signal handlers always remain installed until
     explicitly	changed	by a subsequent	sigaction(2) call, and the signal mask
     operates as documented in sigaction(2).  Programs may switch between
     restartable and interruptible system call operation as often as desired
     in	the execution of a program.

     Issuing a siginterrupt(3) call during the execution of a signal handler
     will cause	the new	action to take place on	the next signal	to be caught.

NOTES
     This library routine uses an extension of the sigaction(2)	system call
     that is not available in 4.2BSD, hence it should not be used if backward
     compatibility is needed.

RETURN VALUES
     The siginterrupt()	function returns the value 0 if	successful; otherwise
     the value -1 is returned and the global variable errno is set to indicate
     the error.

ERRORS
     The siginterrupt()	call fails if:

     [EINVAL]		The sig	argument is not	a valid	signal number.

SEE ALSO
     sigaction(2), sigprocmask(2), sigsuspend(2), signal(3)

HISTORY
     The siginterrupt()	function appeared in 4.3BSD.

FreeBSD	9.2			 June 4, 1993			   FreeBSD 9.2

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | NOTES | RETURN VALUES | ERRORS | SEE ALSO | HISTORY

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