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// -*- C++ -*-
//=============================================================================
/**
* @file OS_Errno.h
*
* $Id$
*
* @author (Originally in OS.h)Doug Schmidt <schmidt@cs.wustl.edu>
*/
//=============================================================================
#ifndef ACE_OS_ERRNO_H
#define ACE_OS_ERRNO_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/OS_NS_errno.h"
/**
* @class ACE_Errno_Guard
*
* @brief Provides a wrapper to improve performance when thread-specific
* errno must be saved and restored in a block of code.
*
* The typical use-case for this is the following:
* int error = errno;
* call_some_function_that_might_change_errno ();
* errno = error;
* This can be replaced with
* {
* ACE_Errno_Guard guard (errno);
* call_some_function_that_might_change_errno ();
* }
* This implementation is more elegant and more efficient since it
* avoids an unnecessary second access to thread-specific storage
* by caching a pointer to the value of errno in TSS.
*/
class ACE_Export ACE_Errno_Guard
{
public:
/// Stash the value of <error> into <error_> and initialize the
/// <errno_ptr_> to the address of <errno_ref>.
ACE_Errno_Guard (ACE_ERRNO_TYPE &errno_ref,
int error);
/// Stash the value of <errno> into <error_> and initialize the
/// <errno_ptr_> to the address of <errno_ref>.
ACE_Errno_Guard (ACE_ERRNO_TYPE &errno_ref);
/// Reset the value of <errno> to <error>.
~ACE_Errno_Guard (void);
#if defined (ACE_HAS_WINCE_BROKEN_ERRNO)
/// Assign <errno_ref> to <error_>.
int operator= (const ACE_ERRNO_TYPE &errno_ref);
#endif /* ACE_HAS_WINCE_BROKEN_ERRNO */
/// Assign <error> to <error_>.
int operator= (int error);
/// Compare <error> with <error_> for equality.
bool operator== (int error);
/// Compare <error> with <error_> for inequality.
bool operator!= (int error);
private:
#if defined (ACE_MT_SAFE)
ACE_ERRNO_TYPE *errno_ptr_;
#endif /* ACE_MT_SAFE */
int error_;
};
#if defined (ACE_HAS_INLINED_OSCALLS)
# if defined (ACE_INLINE)
# undef ACE_INLINE
# endif /* ACE_INLINE */
# define ACE_INLINE inline
# include "ace/OS_Errno.inl"
#endif /* ACE_HAS_INLINED_OSCALLS */
#include /**/ "ace/post.h"
#endif /* ACE_OS_ERRNO_H */
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