DosSetRealVec()               Install real mode interrupt handler
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 Function : Install a real mode interrupt handler

 Syntax   : USHORT BLXAPI DosSetRealVec( USHORT intno,
            REALPTR newhandler, REALPTR _far *prevhandler);

 intno      Interrupt number.

 newhandler Pointer to new handler.

 prevhandlerPointer to a function pointer to receive the address of the
            previous interrupt handler.

 Return   : Address of the previous interrupt handler.

 DosSetRealVec() sets the pointer for the specified real mode interrupt in
 the real mode interrupt vector table. DosSetRealVec() also returns a pointer
 to the previous interrupt handler.

 An example of how to use this function can be found in the files INTMAIN.C,
 INTHAND.ASM and INTMAIN.LNK in the C subdirectory of where Blinker is
 installed.