blob: 2827a162b93634e605aec871def90dffecad3803 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
|
// -*- 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"
ACE_BEGIN_VERSIONED_NAMESPACE_DECL
/**
* @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 @c 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 @c 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:
// Prevent copying
ACE_Errno_Guard (const ACE_Errno_Guard &);
ACE_Errno_Guard &operator= (const ACE_Errno_Guard &);
#if defined (ACE_MT_SAFE)
ACE_ERRNO_TYPE *errno_ptr_;
#endif /* ACE_MT_SAFE */
int error_;
};
ACE_END_VERSIONED_NAMESPACE_DECL
// Inlining this class on debug builds with gcc on Solaris can cause
// deadlocks during static initialization. On non debug builds it
// causes compilation errors.
#if defined (ACE_HAS_INLINED_OSCALLS) && \
(!defined (__GNUG__) || !defined (__sun__))
# 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 */
|
