siginterrupt(3)         (BSD Compatibility Package)         siginterrupt(3)

NAME
     siginterrupt - allow signals to interrupt system calls

SYNOPSIS
     /usr/ucb/cc [flag ...] file ... -lucb

     #include <signal.h>

     int siginterrupt(int sig, int flag);

DESCRIPTION
     siginterrupt 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 is the default behavior when the signal routine is used.

     The siginterrupt() function is used to change the restart behavior
     when a function is interrupted by the specified signal. The function
     siginterrupt(sig, flag) has an effect as if implemented as:

          siginterrupt(int sig, int flag) {
              int ret;
              struct sigaction act;

              (void) sigaction(sig, NULL, &act);
              if (flag)
                  act.saflags &= ~SARESTART;
              else
                  act.saflags |= SARESTART;
              ret = sigaction(sig, &act, NULL);
              return ret;
          }

     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 errno set to
     EINTR. Interrupted system calls that have started transferring data
     will return the amount of data actually transferred.

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

ERRORS
     The siginterrupt() function will fail if:

     EINVAL    The sig argument is not a valid signal number.







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siginterrupt(3)         (BSD Compatibility Package)         siginterrupt(3)

RETURN VALUE
     A 0 value indicates that the call succeeded. A -1 value indicates that
     an invalid signal number has been supplied.

NOTES
     The siginterrupt() function supports programs written to historical
     system interfaces. A portable application, when being written or
     rewritten, should use sigaction() with the SARESTART flag instead of
     siginterrupt().

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

SEE ALSO
     sigaction(2), signal(2), sigblock(3), sigpause(3), sigsetmask(3),
     sigvec(3), signal(3-ucb), signal(5).





































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