DOS Fn 59H: Get Extended Error Info
Compatibility: 3.0+
Expects: AH 59H
BX 0000H (need for 3.x and 4.x)
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Returns: AX extended error code (0 if no error has occurred)
BH error class
BL suggested action
CH location (where the error occurred)
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Info: Use this function to figure out what to do after a DOS function
failed because of an error. You can use this:
■ Inside an INT 24H Critical Error handler
■ After any INT 21H DOS function which signals an error with CF
■ After FCB-style functions which return AL=ffH means an error
See DOS Error Codes for a full listing of possible error codes,
classes, suggested actions, and loci that may be returned by this
function.
Notes: ■ After an error, you get only on chance to call this fn. After
one call, the error condition is unflagged and subsequent calls
won't return meaningful data.
■ You can use fn 5D0aH to simulate an error or set your own
internal error codes.
Versions: This function is not available before 3.00.
With 2.x, when CF returns indicating an error, use your own
program logic to decide what action to take.
With 3.0+, when a function returns CF=1, Microsoft advises to
ignore the error code returned in AX, call this function, and
take the action suggested in BL.
See Also: Fn 5d0aH (set extended error)
System Information Functions
DOS Error Codes
DOS Functions
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