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replacing_20the_20message_20pump [2018/04/13 11:48] – richardrussellreplacing_20the_20message_20pump [2024/01/05 00:21] (current) – external edit 127.0.0.1
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 //by Richard Russell, January 2012//\\ \\  In Windows, every User Interface (UI) thread must have a [[http://en.wikipedia.org/wiki/Message_loop_in_Microsoft_Windows|message pump]] (or message loop), the function of which is to serialise and dispatch incoming messages to their destination windows. \\ \\  In //BBC BASIC for Windows// the message pump is provided by the Run Time Engine, and generally the programmer doesn't need to be aware of it. For anybody who may be interested, this is its C code:\\  //by Richard Russell, January 2012//\\ \\  In Windows, every User Interface (UI) thread must have a [[http://en.wikipedia.org/wiki/Message_loop_in_Microsoft_Windows|message pump]] (or message loop), the function of which is to serialise and dispatch incoming messages to their destination windows. \\ \\  In //BBC BASIC for Windows// the message pump is provided by the Run Time Engine, and generally the programmer doesn't need to be aware of it. For anybody who may be interested, this is its C code:\\ 
 +<code c>
   while (GetMessage (&msg, NULL, 0, 0) != FALSE )   while (GetMessage (&msg, NULL, 0, 0) != FALSE )
        {        {
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            }            }
        }        }
 +</code>
 Very occasionally there may be a requirement to use a different message pump. For example, in order for **keyboard navigation** to work in a dialogue box, the message pump must include a call to the [[http://msdn.microsoft.com/en-us/library/windows/desktop/ms645498(v=vs.85).aspx|IsDialogMessage]] API.\\ \\  Until very recently I believed that it was impossible to //replace// the existing BB4W message pump, and that therefore the only way to provide a different one was to start a new thread (each thread has its own message pump). This is the principal reason why the **WINLIB2** library creates a new thread for every new dialogue box created.\\ \\  However I have discovered that in fact there is a way of replacing the 'main' message pump, and the procedure listed below does exactly that: Very occasionally there may be a requirement to use a different message pump. For example, in order for **keyboard navigation** to work in a dialogue box, the message pump must include a call to the [[http://msdn.microsoft.com/en-us/library/windows/desktop/ms645498(v=vs.85).aspx|IsDialogMessage]] API.\\ \\  Until very recently I believed that it was impossible to //replace// the existing BB4W message pump, and that therefore the only way to provide a different one was to start a new thread (each thread has its own message pump). This is the principal reason why the **WINLIB2** library creates a new thread for every new dialogue box created.\\ \\  However I have discovered that in fact there is a way of replacing the 'main' message pump, and the procedure listed below does exactly that:
  
replacing_20the_20message_20pump.1523620136.txt.gz · Last modified: 2024/01/05 00:16 (external edit)