16 Library introduction [library]

16.5 Library-wide requirements [requirements]

16.5.5 Conforming implementations [conforming]

16.5.5.13 Restrictions on exception handling [res.on.exception.handling]

1
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Any of the functions defined in the C++ standard library can report a failure by throwing an exception of a type described in its Throws: paragraph, or of a type derived from a type named in the Throws: paragraph that would be caught by an exception handler for the base type.
2
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Functions from the C standard library shall not throw exceptions179 except when such a function calls a program-supplied function that throws an exception.180
3
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Destructor operations defined in the C++ standard library shall not throw exceptions.
Every destructor in the C++ standard library shall behave as if it had a non-throwing exception specification.
4
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Functions defined in the C++ standard library that do not have a Throws: paragraph but do have a potentially-throwing exception specification may throw implementation-defined exceptions.181
Implementations should report errors by throwing exceptions of or derived from the standard exception classes ([bad.alloc], [support.exception], [std.exceptions]).
5
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An implementation may strengthen the exception specification for a non-virtual function by adding a non-throwing exception specification.
179)
That is, the C library functions can all be treated as if they are marked noexcept.
This allows implementations to make performance optimizations based on the absence of exceptions at runtime.
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180)
The functions qsort() and bsearch() ([alg.c.library]) meet this condition.
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181)
In particular, they can report a failure to allocate storage by throwing an exception of type bad_­alloc, or a class derived from bad_­alloc.
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