Hello Christopher.
06 Nov 97 16:41, Christopher Butler wrote to All:
 CB> How do I get the address of a member function?
Looking for this?
=== Start cpp_isr.txt ===
Interrupt Handlers as Member Functions
======================================
A static member function of a class can be used as an interrupt handler. It
is not possible to use a "regular" or "normal" member function as an
Interrupt handler because such functions expect a hidden parameter when
called (i.e. the 'this' pointer) and the Intel interrupt mechanism cannot
push the 'this' pointer prior to calling a handler. (See your C++
documentation for more information about the 'this' parameter passed to
member functions).
The following provides an example where a static member function is used as
an interrupt handler. The class also contains a pointer to an instance of
the class, therefore providing more flexibility to the handler. The only
requirement is that the static pointer must be initialized to a valid
instance of the class:
#include 
#include 
#include 
_CLASSDEF( ISR )
class ISR
{
   int intNumber;
   void interrupt (*oldHandler)( ... );
   public:
      static PISR curISR;
      ISR( int );
      ~ISR();
      static void interrupt __handler( ... );
      virtual void handler();
      virtual void justBeep();
};
PISR ISR::curISR = NULL;
ISR::ISR( int iNum )
{
   intNumber = iNum;
   oldHandler = getvect( intNumber );
   setvect( intNumber, (void interrupt (*)( ... ))__handler );
}
ISR::~ISR()
{
   setvect( intNumber, (void interrupt (*)( ... ))oldHandler );
   curISR = NULL;
}
void interrupt ISR::__handler( ... )
{
   if( curISR )
      curISR->handler();
}
void ISR::handler()
{
   justBeep();
}
void ISR::justBeep()
{
   _AX = 0x0e07;
   geninterrupt( 0x10 );
}
int main()
{
   int key = 0;
   ISR myPrintISR( 5 );
   ISR::curISR = &myPrintISR;
   printf( "Hit ESC to terminate or PrintScreen to trigger\n" );
   printf( "the Interrupt 5 and listen to my Beep! \n" );
   while( key != 27 )
   {
      if( !( key = getch() ) )
         key = getch();
      putch( key );
   }
   return( 0 );
}
DISCLAIMER:  You have the right to use this technical information subject
ot the terms of the No-Nonsense License Statement that you received with
the Borland product to which this information pertains.
=== End cpp_isr.txt ===
Don
... IBM: I Blame Microsoft
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