[haiku-3rdparty-dev] Re: Capturing the "NTCH" message

  • From: Stephan Assmus <superstippi@xxxxxx>
  • To: haiku-3rdparty-dev@xxxxxxxxxxxxx
  • Date: Mon, 30 Nov 2009 19:31:35 +0100


On 2009-11-30 at 09:50:46 [+0100], Yashasvi A.C. <yashasviac@xxxxxxxxx> 
> I have been able to capture the "NTCH" messages whenever the state of a 
> specific control changes. For example, when I click the "CheckBox1" 
> control, the NTCH message is intercepted. The order goes like _MUP, ChCl 
> (my customized command message for the control) and then NTCH.
> When I spoke to my supervisor, he told me that the NTCH message was the 
> notification message. I looked at the information in it and it consists 
> of 6 attributes:
> when,   source,     be:value,    be:sender,     be:observe_orig_what, 
> be:observe_change_what.
> We believe this may be the message we were looking for when need to look 
> at a control changing its state.


> The thing is I would like to see whether any of these attributes contain 
> the value "CheckBox1" which I can use for my analysis. I suspect the 
> "CheckBox1" string might be in the sender or source attributes. How do I 
> look at these attributes though? Source is of a B_POINTER_TYPE (void* i 
> think) and sender is BMessenger. I cant just do a toString() style of 
> code to these attributes and view their values, isnt it?

You should definitely read the chapters on messaging in the BeBook. For 
your convenience:



Otherwise one doesn't know where to start to answer these questions, and it 
would mostly be a duplication of the BeBook anyway, until one reaches more 
specific problems that you have.

Best regards,

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