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
127
128
129
130
131
132
133
134
135
136
137
138
|
/* -*- C++ -*- */
// $Id$
// ============================================================================
//
// = LIBRARY
// ace
//
// = FILENAME
// SV_Semaphore_Simple.h
//
// = AUTHOR
// Doug Schmidt
//
// ============================================================================
#if !defined (ACE_SV_SEMAPHORE_SIMPLE_H)
#define ACE_SV_SEMAPHORE_SIMPLE_H
#include "ace/ACE.h"
class ACE_Export ACE_SV_Semaphore_Simple
// = TITLE
// This is a simple semaphore package that assumes there are
// no race conditions for initialization (i.e., the order of
// process startup must be well defined).
{
public:
enum
{
ACE_CREATE = IPC_CREAT,
ACE_OPEN = 0
};
// = Initialization and termination methods.
ACE_SV_Semaphore_Simple (void);
ACE_SV_Semaphore_Simple (key_t key,
int flags = ACE_SV_Semaphore_Simple::ACE_CREATE,
int initial_value = 1,
int nsems = 1,
int perms = ACE_DEFAULT_PERMS);
ACE_SV_Semaphore_Simple (const char *name,
int flags = ACE_SV_Semaphore_Simple::ACE_CREATE,
int initial_value = 1,
int nsems = 1,
int perms = ACE_DEFAULT_PERMS);
~ACE_SV_Semaphore_Simple (void);
int open (const char *name,
int flags = ACE_SV_Semaphore_Simple::ACE_CREATE,
int initial_value = 1,
int nsems = 1,
int perms = ACE_DEFAULT_PERMS);
int open (key_t key,
int flags = ACE_SV_Semaphore_Simple::ACE_CREATE,
int initial_value = 1,
int nsems = 1,
int perms = ACE_DEFAULT_PERMS);
// Open or create one or more SV_Semaphores. We return 0 if all is
// OK, else -1.
int close (void);
// Close a ACE_SV_Semaphore, marking it as invalid for subsequent
// operations...
int remove (void) const;
// Remove all SV_Semaphores associated with a particular key. This
// call is intended to be called from a server, for example, when it
// is being shut down, as we do an IPC_RMID on the ACE_SV_Semaphore,
// regardless of whether other processes may be using it or not.
// Most other processes should use close() below.
// = Semaphore acquire and release methods.
int acquire (int n = 0, int flags = 0) const;
// Wait until a ACE_SV_Semaphore's value is greater than 0, the
// decrement it by 1 and return. Dijkstra's P operation, Tannenbaums
// DOWN operation.
int acquire_read (int n = 0, int flags = 0) const;
// Acquire a semaphore for reading.
int acquire_write (int n = 0, int flags = 0) const;
// Acquire a semaphore for writing
int tryacquire (int n = 0, int flags = 0) const;
// Non-blocking version of <acquire>.
int tryacquire_read (int n = 0, int flags = 0) const;
// Try to acquire the semaphore for reading.
int tryacquire_write (int n = 0, int flags = 0) const;
// Try to acquire the semaphore for writing.
int release (int n = 0, int flags = 0) const;
// Increment ACE_SV_Semaphore by one. Dijkstra's V operation,
// Tannenbaums UP operation.
// = Semaphore operation methods.
int op (int val, int semnum = 0, int flags = 0) const;
// General ACE_SV_Semaphore operation. Increment or decrement by a
// specific amount (positive or negative; amount can`t be zero).
int op (sembuf op_vec[], int nsems) const;
// General ACE_SV_Semaphore operation on an array of SV_Semaphores.
// = Semaphore control methods.
int control (int cmd, semun arg, int semnum = 0) const;
int control (int cmd, int value = 0, int semnum = 0) const;
int get_id (void) const;
// Get underlying internal id.
void dump (void) const;
// Dump the state of an object.
ACE_ALLOC_HOOK_DECLARE;
// Declare the dynamic allocation hooks.
protected:
key_t key_;
int internal_id_;
int sem_number_;
int init (key_t k = ACE_INVALID_SEM_KEY, int i = -1);
key_t name_2_key (const char *name);
// Convert name to key This function is used internally to create
// keys for the semaphores. A valid name contains letters and
// digits only and MUST start with a letter.
//
// The method for generating names is not very sophisticated, so
// caller should not pass strings which match each other for the first
// LUSED characters when he wants to get a different key.
};
#include "ace/SV_Semaphore_Simple.i"
#endif /* _SV_SEMAPHORE_SIMPLE_H */
|