TC: void interrupt (*getvect( int intr_num ))()

	- prototype in dos.h

	- returns the value of the interrupt vector named by intr_num
	- returns 4-byte far pointer to current interrupt service routine
	  stored in interrupt vector table
	- Example:

		void interrupt (*old_int_1c)();

		old_int_1c = getvect( 0x1c );

	- MS C uses _dos_getvect()
	- see	INT 21,35