SIGFLAG(3-SVR4)     RISC/os Reference Manual      SIGFLAG(3-SVR4)



NAME
     sigflag - simplified signal management

SYNOPSIS
     #include <signal.h>

     int sigflag(int sig, int flag, int on)

DESCRIPTION
     sigflag does an logical OR of the sa_flag in the sigaction
     structure associated with signal sig if on is non-zero.If on
     is zero, sigflag does a logical AND of the sa_flag with the
     inverse of flag.

     flags is a logical OR of any of the following values:

     SA_ONSTACK
          If set and the signal is caught and an alternate signal
          stack has been declared with sigaltstack(2), the signal
          is delivered to the calling process on that stack.
          Otherwise, the signal is delivered on the same as the
          main program.

     SA_RESETPAND
          If set and the signal is caught, the disposition of the
          signal is reset to SIG_DFL and the signal will not be
          blocked on entry to the signal handler.  SIGILL,
          SIGTRAP, and SIGPWR cannot be automatically reset when
          delivered; the system silently enforces this restric-
          tion).

     SA_NODEFER
          If set and the signal is caught, the signal will not be
          automatically blocked by the kernel while it is being
          caught.

     SA_RESTART
          If set and the signal is caught, a system call that is
          interrupted by the execution of this signal's handler
          is transparently restarted by the system.  Otherwise,
          that system call returns an EINTR error.

     SA_SIGINFO
          If cleared and the signal is caught, sig is passed as
          the only argument to the signal-catching function.  If
          set and the signal is caught, pending signals of type
          sig are reliably queued to the calling process and two
          additional arguments are passed to the signal-catching
          function.  If the second argument is not equal to NULL,
          it points to a siginfo_t structure containing the rea-
          son why the signal was generated [see siginfo(5)]; the
          third argument points to a ucontext_t structure



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SIGFLAG(3-SVR4)     RISC/os Reference Manual      SIGFLAG(3-SVR4)



          containing the receiving process's context when the
          signal was delivered [see ucontext(5)].

     SA_NOCLDWAIT
          If set and sig equals SIGCHLD, the system will not
          create zombie processes when children of the calling
          process exit.  If the calling process subsequently
          issues a wait(2), it blocks until all of the calling
          process's child processes terminate, and then returns a
          value of -1 with errno set to ECHILD.

     SA_NOCLDSTOP
          If set and sig equals SIGCHLD, sig will not be sent to
          the calling process when its child processes stop or
          continue.

ERRORS
     sigflag will fail with EINVAL if the value of the sig argu-
     ment is not a valid signal number or is equal to SIGKILL or
     SIGSTOP.

DIAGNOSTICS
     On success, sigflag returns 0.  On failure, it returns -1
     and sets errno to indicate the error.

SEE ALSO
     pause(2), sigaltstack(2), signal(2), sigaction(2), wait(2),
     ucontext(5), siginfo(5).



























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