Roving Tandem Debugger

A characteristic of persistent applications is that they can run on any phantom port running FlashConnect. This is not problematic for small development systems that use only one active FlashConnect connection. However, on larger multiuser systems, determining the port on which the application being debugged is running can be a repetitive, time-consuming task.

Roving tandems allow a developer to register as the client of an application, and when the application dictates, allows the developer to automatically tandem to the application from the ports that the application is running.

Roving tandem uses:

WWW-TANDEM, a command that registers the developer as the client of an application and then waits for the application to request a connection.
w3Tandem, an API call that registers the application and connects to any waiting developer.

When the developer registers, a record is written to the w3TandemControl file with the application name and the port number on which the developer is waiting. When the application registers, it adds its port number to the control record. When both port numbers are known, the WWW-TANDEM command connects the developer to the waiting application.

The developer and the application can end the connection. If the application is finished, perhaps having sent information to the user and now stopping until the next page is submitted, it uses the w3Tandem API call to temporarily disconnect the tandem to the developer’s port. The WWW-TANDEM command waits for the application to return, or for the developer to stop the WWW-TANDEM session. When the application runs again, possibly from another port, the tandem between the two ports is automatically re-established.

The following code example provides a simple tandem test:

bp ’w3mvDTandemTest’ size = 24

01 subroutine w3TandemTest

02 include wbp w3include

04 call w3Tandem("test", "Start")

06 call w3HtmlInit("", "")

07 call w3HtmlHeader("","")

08 for i = 1 to 10

09 CRT i

10 call w3Printn("<BR>":i)

11 sleep(1)

12 next i

13 call w3HtmlFooter("","")

15 call w3Tandem("test", "Stop")

16 return

If you are using the command line, type this command at the prompt:

WWW-TANDEM TEST

For more information about the w3Tandem API call and the WWW-TANDEM command, see the FlashConnect Programmer’s Online Reference.