blob: 796a4a052db3847f03fa565039803e5e72819b1e (
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
102
103
104
105
106
107
108
109
110
111
112
113
|
--Copyright: Matra Datavision 1992,1993
-- File: OSD_Semaphore.cdl
-- Created: April 21 1992
-- Author: Stephan GARNAUD (ARM)
-- <sga@sparc4>
class Semaphore from OSD
---Purpose: IPC Tools -Semaphores
-- The semaphores are used to facilitate shared resources.
-- This implementation provides a way to ensure mutual
-- exclusion using 'Lock' and 'Free' primitives.
-- The Lock is used to prevent access if it's not yet allowed.
-- The Free validates the semaphores and if possible, frees process
-- waiting for a common resource.
uses Protection, Error, AsciiString from TCollection
raises ConstructionError, OSDError, ProgramError
is
Create returns Semaphore;
---Purpose: Allocate room for semaphore name.
-- This is to be used with 'Open'.
-- so the process is a client.
---Level: Advanced
Create (Name : AsciiString) returns Semaphore
---Purpose: Instantiates Semaphore object with a name.
-- The name is the only way provided to work with a common
-- semaphore for different processes.
-- Each process working with the same semaphore must use
-- a common known access : the semaphore's NAME.
-- Raises ConstructionError when the name contains characters
-- not in range of ' '...'~'.
-- This is for a server process.
---Level: Advanced
raises ConstructionError;
Build (me : in out) is static;
---Purpose: Sets semaphore (physically) into memory
---Level: Advanced
Open (me : in out ; Name : AsciiString)
---Purpose: Opens (physically) a semaphore
-- Raises ConstructionError when the name contains characters
-- not in range of ' '...'~'.
---Level: Advanced
raises ConstructionError is static;
GetCounter (me : in out) returns Integer is static;
---Purpose: Returns current value of the semaphore's counter.
-- Raises ProgramError when the semaphore is not open.
---Level: Advanced
SetCounter (me : in out; Value : Integer) is static;
---Purpose: Sets the semaphore's counter to a specific value.
-- Raises ProgramError when the semaphore is not open.
---Level: Advanced
Delete (me: out)
---Purpose: Removes the semaphore.
-- This is used only by server process !
-- Raise ProgramError if the semaphore is already deleted.
---Level: Advanced
raises ProgramError is static;
Lock (me: out)
---Purpose: Makes current process waiting for access
-- Raises ProgramError when the semaphore does't exist.
---Level: Advanced
raises ProgramError is static;
Free (me: out)
---Purpose: Frees one access to a semaphore.
-- Raises ProgramError when the semaphore does't exist.
---Level: Advanced
raises ProgramError is static;
Restore (me : in out)
---Purpose: Resets semaphore counter to zero.
-- Raises ProgramError when the semaphore does't exist.
---Level: Advanced
raises ProgramError is static;
Failed (me) returns Boolean is static;
---Purpose: Returns TRUE if an error occurs
---Level: Advanced
Reset (me : in out) is static;
---Purpose: Resets error counter to zero
---Level: Advanced
Perror (me : in out)
---Purpose: Raises OSD_Error
---Level: Advanced
raises OSDError is static;
Error (me) returns Integer is static;
---Purpose: Returns error number if 'Failed' is TRUE.
---Level: Advanced
fields
myName : AsciiString; -- The semaphore name
myKey : Integer;
mySemId : Integer; -- Internal identification of semaphore
myError : Error;
end Semaphore from OSD;
|
