child-list.h

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/*

Copyright (C) 1993-2018 John W. Eaton

This file is part of Octave.

Octave is free software: you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

Octave is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with Octave; see the file COPYING.  If not, see
<https://www.gnu.org/licenses/>.

*/

#if ! defined (octave_child_list_h)
#define octave_child_list_h 1

#include "octave-config.h"

#include <csignal>

#include <sys/types.h>

#include "base-list.h"

namespace octave
{
  class OCTAVE_API child
  {
  public:

    // Do whatever to handle event for child with PID (might not
    // actually be dead, could just be stopped).  Return true if
    // the list element corresponding to PID should be removed from
    // list.  This function should not call any functions that modify
    // the child_list.

    typedef bool (*child_event_handler) (pid_t, int);

    child (pid_t id = -1, child_event_handler f = nullptr)
      : pid (id), handler (f), have_status (0), status (0)
    { }

    child (const child&) = default;

    child& operator = (const child&) = default;

    ~child (void) = default;

    // The process id of this child.
    pid_t pid;

    // The function we call if an event happens for this child.
    child_event_handler handler;

    // Nonzero if this child has stopped or terminated.
    sig_atomic_t have_status;

    // The status of this child; 0 if running, otherwise a status value
    // from waitpid.
    int status;
  };

  class OCTAVE_API child_list
  {
  public:

    child_list (void) { }

    void insert (pid_t pid, child::child_event_handler f);

    void remove (pid_t pid);

    void reap (void);

    bool wait (void);

  private:

    base_list<child> m_list;
  };
}

#endif