Function  59h	Get Extended Error Information		(Dos 3.x)
   Obtains detailed error information after a previous unsuccessful Int 21h 
function call, including the recommended remedial action.
entry	AH	59h
	BX	00h
return	AX	Struct -Extended Error Codes
		0000h	no error occured on last Int 21h function call
		0022h	invalid disk change
			ES:DI	ASCIIZ volume label of disk to insert
	BH	Struct -Extended Error Class
	BL	Struct -Extended Error Action
	CH	Struct -Extended Error Location
note 1) This function may be called after any other Int 21h function all that 
	returned an error status, in order to obtain more detailed information 
	about the error type and the recommended action.
     2) This function may also be called during the execution of a critical-
	error Int\24 handler.
     3) The contents of registers CL,DX,SI,DI,BP,DS, and ES are destroyed
     4) Note that extended error codes 13h-1Fh (19-31) and 22h (34) correspond 
	exactly to error codes 0-0Ch (0-12) and 0Fh (15) returned by Int\24
     5) Microsoft documentation explicitly warns that new error codes will be 
	added in future versions of MS-DOS, and you should not code your 
	programs to recognize only specific error numbers if you want to 
	ensure upward compatibility.

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