[ новости /+++ | форум | теги | ]

NAME
     interrupt Interrupt_handler - signal handling for  the  task
     library

SYNOPSIS
     #include <task.h>
     class Interrupt_handler : public object {
     public:
          // exported constructor
          Interrupt_handler(int signo);
          // exported virtual function
          virtual int pending();
     private:
          // private virtual function
          virtual void interrupt();
     };

DESCRIPTION
     Class Interrupt_handler provides a way for a  task  to  wait
     for  an  external  Unix  signal.   It  is derived from class
     object so that tasks may wait on a handler object.

     Interrupt_handler ih(signo);
          Constructs a new interrupt handler ih, which will  wait
          for  signal  number  signo  (see signal(2)).  When that
          signal occurs, the private virtual function interrupt()
          is  called  immediately,  via  the  usual  Unix  signal
          mechanism.  When the function returns, the  task  which
          was  interrupted  resumes.   That is, interrupts do not
          cause preemption within the task model.

          A special task, the interrupt alerter, is automatically
          created  by  the  task  system.  When a running task is
          suspended and an interrupt has occurred since the  last
          task  suspension,  the  interrupt alerter is scheduled.
          The alerter alerts  the  Interrupt_handlers  associated
          with  any  interrupts which have occured since the last
          time the alerter  ran.   Any  tasks  waiting  for  such
          handlers therefore become runnable.

          In the absence of any interrupt handlers, the  schedul-
          ing  process terminates when there are no more tasks to
          be run.  So long as there are any  interrupt  handlers,
          scheduling  will  not terminate, but will wait indefin-
          itely for any interrupts which may occur.

     int i = ih.pending();
          Always returns ``true''  (non-zero)  except  the  first
          time it is called after an interrupt occurs.

     void interrupt()
          This is a private  virtual  function.   The  base-class
          version does nothing.  Normally you will derive a class
          from Interrupt_handler and define this function  to  do
          whatever  is  appropriate  for  that  class.   See  the
          tutorial for an example.

DIAGNOSTICS
     See task(3C++).

SEE ALSO
     TASK.INTRO(3C++), queue(3C++), task(3C++), tasksim(3C++),
     signal(2)

     Task Library Tutorial

Партнёры:

Хостинг: