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Respond to remote events

Posted by asmall (asmall), 4 July 2007
I'm writing a Command Prompt based test tool in C that includes the TCL language. I'm overriding Tcl_AppINit and adding custom commands using Tcl_CreateObjCommand() and calling Tcl_Main from main().

The system has two processor boards (A & B) that normally interact, and the test tool emulates one side (so we can test the other) by replacing board A with a PC. The original concept was that board A would send data and commands to B, but now it looks more complex.

Now, some commands from A (e.g. dataavailable) result in B calling back to request blocks of data (e.g. getblock). This event arrives at the C program as a callback function.

I need to allow the event to come back into the TCL script and respond appropriately depending on the parameter values in the callback. An idea is to define a TCL proc earlier in the script that can be called from within the C handler, somehow passing on the parameters. The parameters include a number of status flags, and a void pointer to "pDetails".

Can TCL do this?

Posted by admin (Graham Ellis), 6 July 2007
This is one of those questions that I went "oh help" at when I first read it ... and I'm still wallowing slightly - I'm away from home and all my reference books, and looking at Java / Tomcat stuff today which is a very different topic indeed. But I THINK the answer to your question is "Yes".

Pleas do follow up further if you would like me to take a further look and see if I can came up with more certainty for that answer next week, when I'll be back in base

Posted by asmall (asmall), 6 July 2007
Yes, still interested. Currently the callbacks are going to a printf statement so the developers are able to manually confirm the parameters and respond accordingly. This is OK for early development, but we'll need better automation for testing.

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