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ExceptionTypeRegisteredQ[sym]

gives True if sym is a symbol that has been registered as an exception type, and False otherwise.

ExceptionTypeRegisteredQ[sym,tag]

gives True for symbol sym registered as a subtype of exception type tag, and False otherwise.

ExceptionTypeRegisteredQ[sym,{tag1,tag2,…}]

gives True for symbol sym registered as a subtype of any of the tag1, tag2, …, and False otherwise.

Details
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ExceptionTypeRegisteredQ

ExceptionTypeRegisteredQ[sym]

gives True if sym is a symbol that has been registered as an exception type, and False otherwise.

ExceptionTypeRegisteredQ[sym,tag]

gives True for symbol sym registered as a subtype of exception type tag, and False otherwise.

ExceptionTypeRegisteredQ[sym,{tag1,tag2,…}]

gives True for symbol sym registered as a subtype of any of the tag1, tag2, …, and False otherwise.

Details

  • The parent types in the second argument of ExceptionTypeRegisteredQ must be any valid exception types (strings or symbols). They are not required to be registered exception types.
  • ExceptionTypeRegisteredQ[sym,tagspec] will also return True when types in tagspec are some ancestors of sym, not necessarily direct parent types.

Examples

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Basic Examples  (1)

This registers the type ConversionError as a subtype of "GeneralError":

Wolfram Language code: RegisterExceptionType[TypeConversionError, "GeneralError"]

This checks whether the symbols TypeConversionError and tag have been registered:

Wolfram Language code: ExceptionTypeRegisteredQ /@ {TypeConversionError, tag}

The symbol does not need to be registered to be used as a tag, so you can create Exception objects from either of these types:

Wolfram Language code: Exception /@ {TypeConversionError, tag}

This deregisters the type TypeConversionError:

Wolfram Language code: Unprotect[TypeConversionError]; DeleteObject[TypeConversionError]

Scope  (1)

This registers DatabaseError and DatabaseTypeError types, creating exception type hierarchy:

Wolfram Language code: RegisterExceptionType[DatabaseError, "GeneralError"] RegisterExceptionType[DatabaseTypeError, DatabaseError]

This confirms that DatabaseError and DatabaseTypeError are registered exception types, whereas "GeneralError" is a valid, but not registered, exception type:

Wolfram Language code: ExceptionTypeRegisteredQ /@ {DatabaseError, DatabaseTypeError, "GeneralError"}

This checks that DatabaseTypeError is a subtype of DatabaseError, and also a subtype of one of {"GeneralError","SomeOtherError"}:

Wolfram Language code: {ExceptionTypeRegisteredQ[DatabaseTypeError, DatabaseError], ExceptionTypeRegisteredQ[DatabaseTypeError, {"GeneralError", "SomeOtherError"}]}

This deregisters the DatabaseError and DatabaseTypeError types:

Wolfram Language code: Unprotect[DatabaseError, DatabaseTypeError]; DeleteObject /@ {DatabaseTypeError, DatabaseError}
Wolfram Research (2026), ExceptionTypeRegisteredQ, Wolfram Language function, https://reference.wolfram.com/language/ref/ExceptionTypeRegisteredQ.html.

Text

Wolfram Research (2026), ExceptionTypeRegisteredQ, Wolfram Language function, https://reference.wolfram.com/language/ref/ExceptionTypeRegisteredQ.html.

CMS

Wolfram Language. 2026. "ExceptionTypeRegisteredQ." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/ExceptionTypeRegisteredQ.html.

APA

Wolfram Language. (2026). ExceptionTypeRegisteredQ. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/ExceptionTypeRegisteredQ.html

BibTeX

@misc{reference.wolfram_2026_exceptiontyperegisteredq, author="Wolfram Research", title="{ExceptionTypeRegisteredQ}", year="2026", howpublished="\url{https://reference.wolfram.com/language/ref/ExceptionTypeRegisteredQ.html}", note=[Accessed: 12-June-2026]}

BibLaTeX

@online{reference.wolfram_2026_exceptiontyperegisteredq, organization={Wolfram Research}, title={ExceptionTypeRegisteredQ}, year={2026}, url={https://reference.wolfram.com/language/ref/ExceptionTypeRegisteredQ.html}, note=[Accessed: 12-June-2026]}