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C++ API

sighandlers.h

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/*

Copyright (C) 1993, 1994, 1995, 1996, 1997, 2000, 2002, 2005, 2006,
              2007 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
<http://www.gnu.org/licenses/>.

*/

/*

The signal blocking macros defined below were adapted from similar
functions from GNU Bash, the Bourne Again SHell, copyright (C) 1994
Free Software Foundation, Inc.

*/

// This file should always be included after config.h!

#if !defined (octave_sighandlers_h)
#define octave_sighandlers_h 1

// Include signal.h, not csignal since the latter might only define
// the ANSI standard C signal interface.

#include <signal.h>

#include "syswait.h"
#include "siglist.h"

#include "base-list.h"

// Signal handler return type.
#ifndef RETSIGTYPE
#define RETSIGTYPE void
#endif
#ifndef BADSIG
#define BADSIG (RETSIGTYPE (*)(int))-1
#endif

#define BLOCK_SIGNAL(sig, nvar, ovar) \
  do \
    { \
      sigemptyset (&nvar); \
      sigaddset (&nvar, sig); \
      sigemptyset (&ovar); \
      sigprocmask (SIG_BLOCK, &nvar, &ovar); \
    } \
  while (0)

#if !defined (SIGCHLD) && defined (SIGCLD)
#define SIGCHLD SIGCLD
#endif

#if defined (HAVE_POSIX_SIGNALS)
#define BLOCK_CHILD(nvar, ovar) BLOCK_SIGNAL (SIGCHLD, nvar, ovar)
#define UNBLOCK_CHILD(ovar) sigprocmask (SIG_SETMASK, &ovar, 0)
#else
#define BLOCK_CHILD(nvar, ovar) ovar = sigblock (sigmask (SIGCHLD))
#define UNBLOCK_CHILD(ovar) sigsetmask (ovar)
#endif

typedef RETSIGTYPE sig_handler (int);

// FIXME -- the data should probably be private...

struct
octave_interrupt_handler
{
#ifdef SIGINT
  sig_handler *int_handler;
#endif

#ifdef SIGBREAK
  sig_handler *brk_handler;
#endif
};

// Nonzero means we have already printed a message for this series of
// SIGPIPES.  We assume that the writer will eventually give up.
extern int pipe_handler_error_count;

// TRUE means we can be interrupted.
extern OCTINTERP_API bool can_interrupt;

extern OCTINTERP_API sig_handler *octave_set_signal_handler (int, sig_handler *,
                                               bool restart_syscalls = true);

extern OCTINTERP_API void install_signal_handlers (void);

extern OCTINTERP_API void octave_signal_handler (void);

extern OCTINTERP_API octave_interrupt_handler octave_catch_interrupts (void);

extern OCTINTERP_API octave_interrupt_handler octave_ignore_interrupts (void);

extern OCTINTERP_API octave_interrupt_handler
octave_set_interrupt_handler (const volatile octave_interrupt_handler&,
                              bool restart_syscalls = true);

// extern void ignore_sigchld (void);

// Maybe this should be in a separate file?

class
OCTINTERP_API
octave_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 octave_child_list.

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

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

  octave_child (const octave_child& oc)
    : pid (oc.pid), handler (oc.handler),
      have_status (oc.have_status), status (oc.status) { }
 
  octave_child& operator = (const octave_child& oc)
    {
      if (&oc != this)
        {
          pid = oc.pid;
          handler = oc.handler;
          have_status = oc.have_status;
          status = oc.status;
        }
      return *this;
    }

  ~octave_child (void) { }

  // 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
OCTINTERP_API
octave_child_list
{
protected:

  octave_child_list (void) { }

  class octave_child_list_rep : public octave_base_list<octave_child>
  {
  public:

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

    void reap (void);

    bool wait (void);
  };

public:

  ~octave_child_list (void) { }

  static void insert (pid_t pid, octave_child::child_event_handler f);

  static void reap (void);

  static bool wait (void);

  static void remove (pid_t pid);

private:

  static bool instance_ok (void);

  static octave_child_list_rep *instance;
};

#endif

/*
;;; Local Variables: ***
;;; mode: C++ ***
;;; End: ***
*/