SIGINTERRUPT(3) 					   BSD 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
     transferring 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 back-
     ward 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), sigblock(2), sigpause(2), sigsetmask(2), signal(3)

HISTORY

     The siginterrupt() function appeared in 4.3BSD.

BSD
								   June 4, 1993 							       BSD