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
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
|
/* -*- C++ -*- */
// $Id$
// ============================================================================
//
// = LIBRARY
// ace
//
// = FILENAME
// Process_Semaphore.h
//
// = DESCRIPTION
// Wrapper for Dijkstra style general semaphores that work
// across processes.
//
// = AUTHOR
// Doug Schmidt
//
// ============================================================================
#ifndef ACE_PROCESS_SEMAPHORE_H
#define ACE_PROCESS_SEMAPHORE_H
#include "ace/pre.h"
#include "ace/Synch.h"
#if !defined (ACE_LACKS_PRAGMA_ONCE)
# pragma once
#endif /* ACE_LACKS_PRAGMA_ONCE */
#if !(defined (ACE_WIN32) || defined (ACE_HAS_POSIX_SEM) || defined (ACE_PSOS))
#include "ace/SV_Semaphore_Complex.h"
#endif /* !(ACE_WIN32 || ACE_HAS_POSIX_SEM || ACE_PSOS) */
class ACE_Export ACE_Process_Semaphore
{
// = TITLE
// Wrapper for Dijkstra style general semaphores that work
// across processes.
public:
ACE_Process_Semaphore (u_int count = 1, // By default make this unlocked.
const ACE_TCHAR *name = 0,
void * = 0,
int max = 0x7FFFFFFF);
// Initialize the semaphore, with an initial value of <count> and a
// maximum value of <max>.
~ACE_Process_Semaphore (void);
// This method is a no-op, i.e., it doesn't remove the semaphore.
// If you want to remove the semaphore, you must call the <remove>
// method explicitly.
int remove (void);
// Explicitly destroy the semaphore. Note that only one thread
// should call this method since it doesn't protect against race
// conditions.
int acquire (void);
// Block the thread until the semaphore count becomes greater than
// 0, then decrement it.
int tryacquire (void);
// Conditionally decrement the semaphore if count is greater than 0
// (i.e., won't block). Returns -1 on failure. If we "failed"
// because someone else already had the lock, <errno> is set to
// <EBUSY>.
int release (void);
// Increment the semaphore, potentially unblocking a waiting thread.
int acquire_read (void);
// Acquire semaphore ownership. This calls <acquire> and is only
// here to make the <ACE_Process_Semaphore> interface consistent
// with the other synchronization APIs.
int acquire_write (void);
// Acquire semaphore ownership. This calls <acquire> and is only
// here to make the <ACE_Process_Semaphore> interface consistent
// with the other synchronization APIs.
int tryacquire_read (void);
// Conditionally acquire semaphore (i.e., won't block). This calls
// <tryacquire> and is only here to make the <ACE_Process_Semaphore>
// interface consistent with the other synchronization APIs.
// Returns -1 on failure. If we "failed" because someone else
// already had the lock, <errno> is set to <EBUSY>.
int tryacquire_write (void);
// Conditionally acquire semaphore (i.e., won't block). This calls
// <tryacquire> and is only here to make the <ACE_Process_Semaphore>
// interface consistent with the other synchronization APIs.
// Returns -1 on failure. If we "failed" because someone else
// already had the lock, <errno> is set to <EBUSY>.
int tryacquire_write_upgrade (void);
// This is only here to make the <ACE_Process_Semaphore>
// interface consistent with the other synchronization APIs.
// Assumes the caller has already acquired the semaphore using one of
// the above calls, and returns 0 (success) always.
#if defined (ACE_WIN32) || defined (ACE_HAS_POSIX_SEM) || defined (ACE_PSOS)
const ACE_sema_t &lock (void) const;
// Return the underlying lock.
#endif /* ACE_WIN32 || ACE_HAS_POSIX_SEM || ACE_PSOS */
void dump (void) const;
// Dump the state of an object.
ACE_ALLOC_HOOK_DECLARE;
// Declare the dynamic allocation hooks.
protected:
#if defined (ACE_WIN32) || defined (ACE_HAS_POSIX_SEM) || defined (ACE_PSOS)
ACE_Semaphore lock_;
#else
ACE_SV_Semaphore_Complex lock_;
// We need this to get the right semantics...
#endif /* ACE_WIN32 || ACE_HAS_POSIX_SEM || ACE_PSOS */
};
#if defined (__ACE_INLINE__)
#include "ace/Process_Semaphore.inl"
#endif /* __ACE_INLINE__ */
#include "ace/post.h"
#endif /* ACE_PROCESS_SEMAPHORE_H */
|
