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// -*- C++ -*-
//==========================================================================
/**
* @file Synch_Options.h
*
* @author Douglas C. Schmidt <d.schmidt@vanderbilt.edu>
*/
//==========================================================================
#ifndef ACE_SYNCH_OPTIONS_H
#define ACE_SYNCH_OPTIONS_H
#include /**/ "ace/pre.h"
#include /**/ "ace/ACE_export.h"
#if !defined (ACE_LACKS_PRAGMA_ONCE)
# pragma once
#endif /* ACE_LACKS_PRAGMA_ONCE */
#include "ace/Time_Value.h"
ACE_BEGIN_VERSIONED_NAMESPACE_DECL
/**
* @class ACE_Synch_Options
*
* @brief Contains the values of options used to determine the
* synchronous and asynchronous behavior.
*
* The supported set of options is depicted in the following table.
* The Reactor column indicates whether or not the USE_REACTOR option is
* supplied.
* The Timeout column specifies the period of time specified by the object;
* Unused implies that USE_TIMEOUT is not included in the options and the
* default timeout value, ACE_Time_Value::zero, is specified, either
* explicitly or by default.
*
* <TABLE>
* <TR><TD align="center"><B>Reactor</B></TD><TD align="center"><B>Timeout</B></TD><TD><B>Behavior</B></TD></TR>
* <TR><TD>yes</TD><TD>Unused</TD><TD>Infinite timeout (using Reactor);
* this is the default.</TD></TR>
* <TR><TD>yes</TD><TD>time</TD><TD>Try asynch transaction for the
* specified time (using Reactor)</TD></TR>
* <TR><TD>yes</TD><TD>0,0</TD><TD>Poll; try, if EWOULDBLOCK, return
* immediately (using Reactor)</TD></TR>
* <TR><TD>no</TD><TD>Unused</TD><TD>Block until completion (don't use Reactor)</TD></TR>
* <TR><TD>no</TD><TD>time</TD><TD>Wait up to specified amount of time for
* completion (don't use Reactor)</TD></TR>
* <TR><TD>no</TD><TD>0,0</TD><TD>Poll and return immediately</TD></TR>
* </TABLE>
*/
class ACE_Export ACE_Synch_Options
{
public:
/// Options flags for controlling synchronization.
/**
* Note that these flags can be bit-wise "or'd" together if both
* options are desired.
*/
enum
{
/// Use the Reactor.
USE_REACTOR = 01,
/// Use the supplied timeout value.
USE_TIMEOUT = 02
};
/**
* Initialize the object to default values unless specified otherwise.
*
* @param options Specifies the options to use; default is neither option
* (no reactor, no timeout).
* @param timeout Specifies the period of time to use for the operation's
* timeout. The default is ACE_Time_Value::zero, noted as
* 0,0 in the behavior options table. If a non-zero timeout
* is specified, the USE_TIMEOUT option is added to
* @a options.
* To use a zero timeout, USE_TIMEOUT must be explicitly
* specified in @a options.
* @param arg A completion tag that can be passed through the options;
* the class using ACE_Synch_Options can access this.
* ACE_Synch_Options makes no use of it internally.
*/
ACE_Synch_Options (unsigned long options = 0,
const ACE_Time_Value &timeout = ACE_Time_Value::zero,
const void *arg = 0);
/// Initialize the object; arguments are the same as for the
/// constructor.
void set (unsigned long options = 0,
const ACE_Time_Value &timeout = ACE_Time_Value::zero,
const void *arg = 0);
/// Returns true if the specified option(s) are enabled, false otherwise.
bool operator[] (unsigned long option) const;
/// Adds the specified option(s) to the object; does not replace them.
void operator= (unsigned long option);
/// Returns the "magic cookie" argument.
const void *arg () const;
/// Set the "magic cookie" argument.
void arg (const void *);
/// Returns a reference to the ACE_Time_Value. This value only makes
/// sense if (*this)[USE_TIMEOUT] is true.
const ACE_Time_Value &timeout () const;
/// Set the timeout value. This method does not alter the options; in
/// particular, it doesn't add USE_TIMEOUT to the options when a non-zero
/// timeout is specified as the constructor and set() do.
void timeout (const ACE_Time_Value &tv);
/**
* Returns a timeout pointer if (*this)[USE_TIMEOUT] is true, else 0.
* This should be used with care, e.g., the timeout pointer should not
* be stored in a manner that will lead to dangling pointers.
*/
const ACE_Time_Value *time_value () const;
// = Static data members (singletons)
/// This is the default setting for options, which will block
/// synchronously.
static ACE_Synch_Options defaults;
/// This is the default synchronous setting.
static ACE_Synch_Options synch;
/// This is the default asynchronous setting.
static ACE_Synch_Options asynch;
/// Dump the state of an object.
void dump () const;
/// Declare the dynamic allocation hooks.
ACE_ALLOC_HOOK_DECLARE;
private:
/// Keeps track of the enabled options.
unsigned long options_;
/// Amount of time to wait for timeouts.
ACE_Time_Value timeout_;
/**
* "Magic cookie" always passed in as an argument to the ACE_Reactor's
* schedule_timer() method. Used to communicate values for
* asynchronous programming.
*/
const void *arg_;
};
ACE_END_VERSIONED_NAMESPACE_DECL
#include /**/ "ace/post.h"
#endif /* ACE_SYNCH_OPTIONS_H */
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