| Chapter 7. The PPCS Server for SBME Databases (PPSR) Component | ||
|---|---|---|
 | Part II. C-Language Components |  |
Chapter 7. The PPCS Server for SBME Databases (PPSR) Component
Table of Contents
Contains a server to allow SBME databases to be accessible to a PPCS client. The server is an object which is configured and controlled by SIMPOL
ppcstype1server
Description
A ppcstype1server object provides access to SBME databases to clients using PPCS type 1 over UDP.
Type Tags
None
Object Value
Properties
| Property | Type | Description |
|---|---|---|
| _ | type(*) | This property is provided for use by the user to attach any object of any type to the type in which this property is provided. |
| __ | type(*) | This property is provided for use by the user to attach any object of any type to the type in which this property is provided. It has the additional feature of being marked with the resolve keyword, so that object resolution can continue down this property. |
| firstsbme | ppcstype1serversbme | Specifies the object which represents the first SBME file used by the server. |
| firstudpport | ppcstype1serverudpport | Specifies the object which represents the first UDP port used by the server. |
| serving | boolean | Indicates whether or not the there is currently a pending call to the .serve() method of the ppcstype1server object. |
| type | type | Specifies the ppcstype1server type object. |
Methods
addsbme()
Description
Adds an SBME file to the ring of SBME files in use by the server.
Prototype
ppcstype1servervar.addsbme (
string filenamecommittypelocktimeoutcachesizerecordcountcodepageerror
Parameters
| Parameter | Default value | Type name | Description |
|---|---|---|---|
| filename | None | string | Specified the SBME file to add to the server, by giving its path and name. |
| committype | "" | string |
Specifies when changes to the SBME file are to be committed. If this is ""
then changes are committed only when the
commit method is called for the SBME object.
If the committype is "auto" then changes are
committed after every change is complete. Committing after every
change means that the SBME file is more secure against system
or programming errors, but there may be a performance penalty.
|
| locktimeout | .inf | integer |
Gives the length of time that a record lock is respected for, measured in
microseconds. When a client locks a record (or all records for a
table) then that lock must be released by the client within the
locktimeout time period. If not then the
server will release the lock, and the client may encounter an
error if it attempts an operation which assumes that the lock is
still in place. A locktimeout of
.inf means that the server will never
automatically release records locks for tables in the new SBME
file.
|
| cachesize | Platform dependent | integer | Specifies the amount of memory to reserve for caching for the new SBME file. |
| recordcount | .true | boolean | Specifies whether a record count should be performed when the tables are added. If the record count is not done, it will be set to 4294967280 (0xfffffff0). This can be an advantage when sharing very large tables, since the record count may be seldom needed, but the time it takes to calculate it can be 7 minutes or more for large tables (more than 1GB in size). |
| codepage | 850 | integer | Specifies the code page to be used for sending and receiving data. The default code page is 850, the DOS Latin 1 code page. Other supported code page values include: 437 (US ASCII), 720 (Arabic), 737 (Greek), 775 (Baltic Rim – Estonian, Lithuanian, and Latvian), 852 (Latin 2 – Eastern European languages), 855 (Cyrillic), 857 (Turkish), 862 (Hebrew), 866 (Cyrillic), 874 Thai, and 1258 (Vietnamese). It is important that the client also be set to open the table using the same code page. |
| error | .nul | integer |
Specifies an object which is used to output any error code generated during
creation of the ppcstype1serversbme object. If
error is not specified or is
.nul then any error which occurs during object
creation will halt the program. If an error object is specified
and an error occurs during object creation then the error code is
output into that object and the method returns
.nul.
|
addudpport()
Description
Adds a port to the ring of ports in use by the server.
Prototype
ppcstype1servervar.addudpport (
integer udpporttxfactorerror
Parameters
| Parameter | Default value | Type name | Description |
|---|---|---|---|
| udpport | None | integer | Gives the number of the UDP port which the ppcstype1server object is to start using. |
| txfactor | 0 | integer | This value is used to throttle the speed at which packets are sent. The value 0 means no throttling. If a value is specified that is too high to be useful, then the highest most meaningful value will be used. |
| error | .nul | integer |
Specifies an object which is used to output any error code generated during
creation of the ppcstype1serverudpport object. If
error is not specified or is
.nul then any error which occurs during object
creation will halt the program. If an error object is specified
and an error occurs during object creation then the error code is
output into that object and the method returns
.nul.
|
break()
Description
Breaks out of all pending calls to the server method.
Prototype
ppcstype1servervar.break ()
Parameters
None
serve()
Description
Instructs the ppcstype1server object to process requests from PPCS clients.
Prototype
ppcstype1servervar.serve (
integer timeouterror
Parameters
| Parameter | Default value | Type name | Description |
|---|---|---|---|
| timeout | 0 | integer |
Specifies the length of time in microseconds to wait for client requests and
process them. If this argument is 0 then the
object will process pending requests but not wait for any length
of time. If timeout is not
0 then this method will block for the
specified length of time, or until it is explicitly broken, by
the break method.
|
| error | .nul | integer |
Specifies an object which is used to output any error code generated during
the processing of client requests. If error is
not specified or is .nul then any error which
occurs during object creation will halt the program. If an error
object is specified and an error occurs during object creation
then the error code is output into that object.
|