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The roots of checked exceptions go back to the [[CLU programming language]]'s notion of exception specification.<ref name=Mindview/> A function could raise only exceptions listed in its type, but any leaking exceptions from called functions would automatically be turned into the sole runtime exception, {{code|failure}}, instead of resulting in compile-time error.<ref name="CLU">{{cite journal |last1=Liskov |first1=B.H. |last2=Snyder |first2=A. |title=Exception Handling in CLU |journal=IEEE Transactions on Software Engineering |date=November 1979 |volume=SE-5 |issue=6 |pages=546–558 |doi=10.1109/TSE.1979.230191 |s2cid=15506879 |url=http://csg.csail.mit.edu/CSGArchives/memos/Memo-155-3.pdf |access-date=19 December 2021}}</ref> Later, [[Modula-3]] had a similar feature.<ref>{{cite web |url=http://www1.cs.columbia.edu/graphics/modula3/tutorial/www/m3_23.html#SEC23 |title=Modula-3 - Procedure Types |publisher=.cs.columbia.edu |date=1995-03-08 |access-date=2011-12-15 |url-status=live |archive-url=https://web.archive.org/web/20080509143753/http://www1.cs.columbia.edu/graphics/modula3/tutorial/www/m3_23.html#SEC23 |archive-date=2008-05-09 }}</ref> These features don't include the compile time checking that is central in the concept of checked exceptions.<ref name=Mindview>{{cite web |url=http://www.mindview.net/Etc/Discussions/CheckedExceptions |archive-url=https://web.archive.org/web/20020405175011/http://www.mindview.net/Etc/Discussions/CheckedExceptions |url-status=dead |archive-date=2002-04-05 |title=Bruce Eckel's MindView, Inc: Does Java need Checked Exceptions? |publisher=Mindview.net |access-date=2011-12-15 }}</ref>
Early versions of the C++ programming language included an optional mechanism similar to checked exceptions, called '''exception specifications'''. By default any function could throw any exception, but this could be limited by a {{Cpp|throw}} clause (similar to the {{Java|throws}} clause in Java) added to the function signature, that specified which exceptions the function may throw
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C++ <code>throw</code> clauses could specify any number of any types, even primitives and classes that did not extend <code>std::exception</code>.
Exception specifications were not enforced at compile-time. Violations resulted in the global function {{Cpp|std::unexpected}} being called.<ref name=bjarne-exc>[[Bjarne Stroustrup]], ''[[The C++ Programming Language]]'' Third Edition, [[Addison Wesley]], 1997. {{ISBN|0-201-88954-4}}. pp. 375-380.</ref> An empty exception specification could be given, which indicated that the function will throw no exception. This was not made the default when exception handling was added to the language because it would have required too much modification of existing code, would have impeded interaction with code written in other languages, and would have tempted programmers into writing too many handlers at the local level.<ref name=bjarne-exc/> Explicit use of empty exception specifications could, however, allow C++ compilers to perform significant code and stack layout optimizations that are precluded when exception handling may take place in a function.<ref name=cppeh /> Some analysts viewed the proper use of exception specifications in C++ as difficult to achieve.<ref>{{cite journal | title=Ten Guidelines for Exception Specifications | last=Reeves | first= J.W. | journal=C++ Report | volume=8 | issue=7 |date=July 1996}}</ref> This use of exception specifications was included in [[C++98]] and [[C++03]], [[deprecated]] in the 2012 C++ language standard ([[C++11]]),<ref>{{cite web |url=http://herbsutter.com/2010/03/13/trip-report-march-2010-iso-c-standards-meeting/ |title=Trip Report: March 2010 ISO C++ Standards Meeting |last=Sutter |first=Herb |author-link=Herb Sutter |date=3 March 2010 |access-date=24 March 2010 |url-status=live |archive-url=https://web.archive.org/web/20100323082634/http://herbsutter.com/2010/03/13/trip-report-march-2010-iso-c-standards-meeting/ |archive-date=23 March 2010 }}</ref> and was removed from the language in [[C++17]]. Throws clauses were replaced by {{Cpp|noexcept}} clauses. A function that will not throw any exceptions would now be denoted by the {{Cpp|noexcept}} keyword, and instead {{Cpp|noexcept(false)}} specified that a function will throw. One can also specify that a function is <code>noexcept</code> conditionally on another function being <code>noexcept</code>, like so:
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